


Far From Shore

by Legendaerie



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe - Sirens and Sailors, Canon-Typical Violence, Implied/Referenced Abuse, M/M, MerMay, Past Abuse, Xenobiology
Language: English
Status: Completed
Published: 2020-05-24
Updated: 2020-11-28
Packaged: 2021-03-02 19:13:41
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 9
Words: 27,125
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24361882
Author URL: https://archiveofourown.org/users/Legendaerie/pseuds/Legendaerie
Summary: A farmer’s son flees to the ocean to make his own way in life, and when his fishing vessel catches a dying siren - a creature only spoken of in warnings and legends - he ends up quite quickly out of his depth.(siren!Felix/fisherman!Sylvain AU)
Relationships: Felix Hugo Fraldarius/Sylvain Jose Gautier
Comments: 240
Kudos: 528





	1. Chapter 1

**Author's Note:**

> I didn’t mean to do anything for MerMay and then Lily made a tweet and if I had to watch POTC4 in theaters for 12 US dollars than I will get my moneys worth out of this concept.
> 
> https://twitter.com/lilymrosenthal/status/1258472789587025920?s=21

The ocean is big enough to hide all sorts of secrets. 

Sylvain wasn’t born on the sea; he doesn’t have the brine in his blood, as the men under him say. But he knows how to read the clouds and the winds, and he has gained his small crew’s trust. Together they’ve made a fair profit fishing in the deep waters far off the Fodlan coast for the past three years. It’s been a good life.

A shame that it will end so soon.

Sylvain raises his hand to his eyes, squinting into the sky. The gulls are circling; with a thoughtful bite to his lip he adjusts the ships wheel, adjusting the sailboat’s course. Must be something dead in the water, drawing all the fish and birds out here. He didn’t expect to cast his net this far away from the coast.

“Are the nets prepared?” he calls out, his short red hair catching the sunlight in a blaze of orange.

The response is immediate. “Aye, aye, captain!” cries his bosun, Raphael, echoed by Caspar and Ashe.

“We’ll be ready to cast ‘em in just a few leagues, I gauge. Right, Ignatz?”

Up in the crow’s nest, his best scout shouts down a more precise reading. “Six and three quarters, captain!”

Sylvain shrugs. Close enough. “Is Linhardt awake? We’ll need all hands on those nets.”

“I’ll go fetch him,” volunteers Alois, the oldest member of the crew, ambling over to the hatch and hauling it open. There’s an audible intake of air as he inhales; Sylvain covers his ears and watches both Caspar and Raphael do the same. “LINHARDT! YOU’RE NEEDED ON DECK!”

A pause, then the last member of their crew emerges in the late morning sunlight, his long hair billowing around him like seaweed.

“You don’t have to yell,” he says, yawning.

Sylvain grins down at him. “Actually, we kind of do,” he replies.

“Half a league!” Ignatz calls down. Immediately, Sylvain snaps back into business.

“Everyone on the nets!”

His crew scatter according, each to their station. This was the part that took Sylvain the longest to learn, and even he can hesitate sometimes.

“Heave!” he calls, and as one they toss the weighted edge of the net overboard. The ship sails on, the rope net rivering over the side as it stretches out, ensnaring the fish schooling just below the surface. Sylvain waits, eyes on Ignatz above them in the crows nest as he scrambles down to join them, then hauls on another rope.

“Heave!” he cries again, and all hands join him. Pulling the rope in, hand over hand, they close the mouth of the net. They can feel the fish fighting them as the net closes, more and more frantic as they’re unable to escape.

Even through his callouses, Sylvain can feel the burn of the rope. Must be a big catch.

“Heave!” he tells them, one more time, and as one they pull the net in and over the side. Foot by foot, fighting the weight of their catch and the will to live of a hundred silver-scaled fish, they haul their net in.

Sylvain sees it first but doesn’t understand it. A flash of pale flesh, deep blue scales and jagged scars. A large predator fish, perhaps chewed on by a whale or shark and left to rot in the ocean. 

Then Caspar screams. _“Siren!”_

Raphael freezes. Alois swears and goes white as bone. Ignatz jumps away from the net, dropping the rope and making the sign of the Saints over his chest.

“What?” Sylvain asks, baffled. And then he looks again.

He wasn’t born on the ocean. The tales he grew up on focused on the wolves and the bears that would prey on his parents livestock, the horrors of the woods. Monsters of fur and fang and shadow were what haunted his nightmares as a child, not this. Not a man, half drowned and starved, ink black hair clinging to his neck and shoulders, with raised spines running down his back. Not a fish with cerulean scales like the waters in the tropical reefs and long tail fins as delicate as a woman’s silk petticoats. Not a being made of both these things, skin above and scales below, gasping among the flopping remains of his catch.

“By the Goddess,” he breathes.

Alois raises a harpoon. “Get back, Captain,” he says, voice shaking. “We’ve got to kill it before it starts singing.”

Sylvain’s hand snaps out and catches the weapon before it can strike. “Kill it? It’s a person.”

“That’s no person. That’s a siren,” Ashe explains, his hands shaking and his complexion as pale as his mist-grey hair. “That’s— the most deadly thing on the ocean.”

Sylvain looks down at the creature on his deck, narrow shoulders heaving. As he watches, one orange-gold eye cracks open and stares at him. It meets his gaze and slides past to the harpoon in his hand, then back. Asking him. Daring him.

“It’s sentient,” he breathes, shoving Alois back. He fixes the rest of his crew with a glare. “I’m not killing anything that’s as smart and as alive as the rest of us.”

“Captain—“

His mind has been made up. Sylvain wades through the flopping mess of fish and tosses the net aside. The siren is tangled in the rope and winces as it’s wrenched around by the motion; Sylvain pulls a knife and starts to saw through the ropes of the net, one at a time.

“Easy, easy,” he shushes as it starts to thrash. Raphael moans in horror. “Hold still. You’re making it worse—“

With a flash of movement, the siren strikes. 

It buries its teeth into the meat of Sylvain’s hand, slitted eyes burning like Hellfire itself, snarling. Beads of light and blood well from where the sharp teeth meet in his flesh, but Sylvain steels himself. He’s seen eyes like that before in wounded animals, in mirrors - he holds that gaze and waits.

“I won’t hurt you,” Sylvain says, just low enough for the siren to hear. His words are heavy with sincerity, more than he meant them to be. The siren opens its mouth, slowly, easing it away from the bite.

Sylvain glances at the wound. The skin around the punctures is edged in a shimmery, oily blue.

“Are they venomous?” he asks, turning. The only crew member left anywhere near the net is Linhardt, who tilts his head to the side.

“No. That’s a mermaid mark. Once they bite you and get a taste of your blood, they’re supposed to be able to track you anywhere in the ocean to find you and kill you. If they don’t kill you on the second bite, of course.”

Huh. “But not venomous?”

Linhardt shakes his head.

Sylvain looks back down at the siren. It’s watching him cautiously, still half tangled in the net. “All right,” he says, shaking the blood off and resuming his work untangling the siren from the ropes.

It’s skinny. Even a man raised on a farm could tell that if it was thrown back overboard it wouldn’t last a day. Sylvain worries his lip between his teeth as he works the siren free, fingers brushing over a scar at the beasts hip right along where the skin and scales meet. The siren flinches but doesn't struggle, closing its eyes again.

“You said they sing?” he looks again to Linhardt. “What kind of song?”

“I don’t know. I found that part boring.”

Sylvain looks at the rest of his crew cowering on the far end of the desk. They’re shivering in the sun like their boat has crossed into the icy waters of the southern pole.

“Shouldn’t it have started singing by now?” 

Raphael and Caspar exchange glances, but it’s Ashe who speaks.

“Captain.” He swallows. “We’ve got a tiger by the tail. You’ve got to throw it back.”

“It’ll _die_ if we do.”

“Better it than us!” blurts Caspar. “These things; they’re terrifying. Can hypnotize an entire shipful of men into doing whatever they want ‘em to. Can tear your throat out with their teeth.”

Sylvain looks at the siren at his knees; with its eyes closed, it’s easy to believe it’s already dead.

Gently, he stands and scoops the siren up in his arms, cradling it against his chest. The creature's head fits neatly under his chin.

“I’m the captain,” he says, staring back at his crew. “I say we keep it until it’s strong enough to swim on its own.”

Without another word, he carries the siren to his cabin, expression firm. Behind that, though, his pulse is racing, waiting to see if those teeth will sink into his neck with grim curiosity. 

Nothing happens. The siren is limp in his arms, cradled against his chest. Linhardt opens the cabin door for him.

“Do you want me to fetch you some seawater?” he asks.

Sylvain shoots him a curious look.

“For the siren. You’re going to put it in your bathtub, right?”

“Ah.” Actually, he’d planned on putting it in his bed, but the tub sounds like a much better idea. He thinks he sees gills along its sides, in between its human-like ribs. “I would appreciate that.”

Linhardt nods, and closes the door behind him.

The claw foot tub is the largest and brightest thing in his quarters. He’d brought it along as a joke at first, then found the elaborate thing to be quite useful for holding guts and bait between trips and - between those uses, once thoroughly scrubbed with lye and sand - lovely to stretch out in for a hot soak after a warm day. It’s empty right now, perhaps with little traces of fish blood along the seams, and Sylvain eases the siren into it.

It appears to be unconscious, head flopping back to rest on the rim of the tub. Sylvain places two fingers along its throat, checking for a pulse. He finds one, fluttering and faint. And then as his touch slides along he discovers a scar puckered unlike the others.

He brushes the siren’s long blue-black hair out of the way and sees, very clearly, the mark of human stitches.

“Did someone take your voice?” he wonders aloud, stroking along the scar. The skin under his fingertips is cool and silky smooth, pleasant to the touch.

Sylvain snatches his hand away, breathing hard. He shakes his head, trying to focus his thoughts on the present and swallows. He’d better get back on deck before his men stage a mutiny.

He helps them pack away the rest of the catch as Lindhart lines up buckets of water at his door, eats with them below decks in silence; and when he retires to his cabin to chart the next day's course the awful tension in the air remains.

The siren hasn’t moved since it was placed in the tub. It doesn’t so much as twitch as Sylvain pours the seawater in, though as the water rehydrates the fine fins at the ends of its tail and near its hips, the translucent membranes are stirred by the motion of each new bucket’s contents. He thinks he can see the gills along its side move as well, fluttering like a shark’s slits.

Sylvain rests his arms along the side of the tub, allowing himself to trail a finger across the surface of the water. “They’re going to kill me for you, you know,” he addresses the siren conversationally. “They’re going to mutiny and chop us both up for bait. Oh well. I had a good run.”

That’s a lie. He had a terrible one, when you look at the big picture. Shouldn’t have assumed that when his parents kicked his brother out, that they did it to protect their younger son from his blows. Too foolish to see that it was proof of a conditional love.

He stares at his hand. The punctures from the bite have been treated and wrapped but he can feel them throbbing under the linen, a constellation of poor decisions and pain.

“Sleep well, siren. I hope we both wake up tomorrow.”

And with that, he stands and crosses the room to the little desk by his bed, lights the lamp with a flick of a match and charts as best he can with an injured hand.


	2. Chapter 2

Sylvain is awoken in the middle of the night to a heavy thud. He snatches the sword from under his pillow and leaps to his feet, eyes wide and taking in his bedroom edged faintly in blue moonlight.

There’s a shape on the floor, shimmering and shining. It crawls towards the window in uneven, jerking movements. His instinct immediately is to run it through, but as it moves its face is bathed in moonlight and he’s struck dumb by the beauty of those almost human features.

“Whoa, whoa, whoa,” and Sylvain returns the sword, lighting the oil lamp at his bedside as he does. “Easy, siren.”

It hisses; a voiceless, furious noise.

He kneels and scoops it up anyway, keeping his voice low and gentle. “I know, I know. You’re the terror of the nine seas. Come here.”

It presses its mouth against his throat and bares its teeth, but it again doesn’t bite him. Pleased and thoughtless, he brushes his lips against its hairline.

“Easy,” he murmurs. “I promised I won’t hurt you. I intend to keep that promise.”

It doesn’t struggle as it’s put back in the tub, though it does glare at him. Sylvain stays leaned over it for a moment, their faces still close together. Those eyes are stunning; hot as firelight and distant as moonlight.

His eyes. Beautiful as he is, the siren’s features are distinctly masculine.

The ship lurches under his feet, and Sylvain stumbles, falling away from the siren and catching himself before he hits the ground.

“Right, okay. Right. Uh. Are you hungry?” he asks the siren.

The siren stares back, expression flat. Sylvain mimes eating with a fork and knife, then thinks better of it and bares his teeth, sinking them into an invisible leg of chicken held between his hands and shaking his head.

“Food?” he asks again.

This time, there’s a little flicker in the siren’s expression. Understanding, maybe. Hopefully. He looks intelligent enough.

Sylvain nods. “Yeah, you’re following me. So, what, you probably eat fish, right?”

He purses his lips and places his hands on either side of his head, flapping them to imitate gills. The siren snorts and looks away quickly. Sylvain’s heart pounds in his chest.

That was a laugh. In any language. He made the siren laugh.

“Hey, I’m doing the best I can,” he laughs back. “Come on, buddy. Are you hungry for fish?”

The siren looks at him from the corner of his eye. Dips his head, slowly and subtly. Raises it again.

A nod.

Sylvain’s smile widens. “All right. One raw fish, coming right up. Stay here, all right? You’re gonna dump that tub if you keep trying to escape, and it’s gonna take me all night to clean this cabin up if you do.”

Another nod.

Satisfied, he heads out and down into the cargo hold where their most recent catch sits in huge metal tanks of cold sea water. He grabs a fish at random and hurries back to his cabin, just in time for the siren to hit the floor again.

“Guess you’re smart enough to lie to me, too, huh?”

Once again, he picks up the siren (who only sighs and goes limp in his arms) and eases it back into the tub. He takes the fish Sylvain offers and turns away to eat it, hunched over the whole fish as he tears it apart, presumably, with his teeth.

The pointed scales down his back are a line Sylvain wants to trace with his fingers, but he clears his throat and looks away.

He waits there, kneeling, until the wet sounds of teeth tearing through flesh have died down. Rubs at the bandage on his bitten hand and thanks the stars the siren didn’t do more damage.

“So. My name is Sylvain. Sylvain—“ he hesitates on the family name, the once easy introduction stumbling. “—Gautier. I’m the captain of this little fishing vessel, and I want to help you.”

The siren’s head tilts ever so slightly in his direction. He thinks he can see, through the mess of damp dark hair, one delicate pointed ear.

“You’re hurt. And you’re sick, I think. So… I’m going to make sure you get better before I put you back, okay? I promise.”

The siren turns around then, reaches out and cups Sylvain’s face with one hand. His eyes burn like twin suns in his pale face, and the words feel pulled out of Sylvain’s chest as they tumble out of his mouth.

_“I swear to return you to the ocean alive.”_

The siren blinks, and the supernatural light in his eyes vanishes. His hand retracts and Sylvain shivers, feeling the wet patch on his cheek in the aftermath as he breathes, shaking and unsure. The siren turns away from Sylvain once more.

That— was magic. Without a doubt, that was magic.

Sylvain stands, rubbing his throat. Hurt and fear swirl in his chest, and he lets it show in his words. “You didn’t have to do that, you know.”

The siren flicks his tail, shifting again in the bathtub. In the yellow lamplight and the blue moonlight, the myriad of scars on his back stand out hot and red against both scales and skin. There are too many for a normal life on the ocean.

“Don’t do that to me again,” he amends. “I get it. But don’t— test me like that. Just ask me what I mean.”

The siren looks back at him from the corner of one eye, and curls himself up in the bathtub even more tightly.

Sylvain watches the siren for another minute, then huffs and shakes his head. “I’m going back to bed. And you’d better not make a break for it in the night again, all right?”

The siren’s tail flickers. It could be a rude gesture as much as a confirmation. He doesn’t speak fish.

And yet he climbs into bed anyway, and after a long and restless hour finally falls back to sleep.

* * *

No one kills anyone during the night, and when Sylvain rises again the siren is still in the tub, combing his hair with his fingers. At the sound of Sylvain pulling his boots on, he lets it fall loose and ducks deeper into the tub, hiding so only his eyes appear over the rim.

It’s cute. Sylvain rubs a hand over his face and clears his throat. “Good morning.”

The tail flicks. The eyes stay steadily watching him.

“I’ve got to get on deck to help the rest of the crew. We’re a fishing vessel, and we’ve got to fill up our hold with fish before we return to port. They’re gonna need my help to do that.”

The siren blinks.

Sylvain stretches slowly, flexing freckled arms that were already tanned and thick with corded muscle from his years on the farm, and pulls on a fresh shirt. “You need anything this morning?” he asks, looking back.

The siren hides a little deeper in the tub, but shakes his head.

Well. That’s some level of communication, at least. 

“If you need me,” he starts, cutting himself off. The siren doesn’t appear to be able to speak or move outside of his tub. Sylvain’s brown eyes take in his small, cluttered cabin and land on a bell mounted on the wall near the door.

“If you need me,” he continues, casting about until he finds a length of long leather cord, tying one end to the rope on the bed, “pull on this, okay?”

He tugs lightly on the cord. The bell rings out sharp and clear in the confined space. Sylvain offers the cord to the siren, waiting patiently.

The hand that takes the cord is delicate, with sharp nails and thin skin. Sylvain can see the veins and tendons underneath shifting as those long fingers curl around the cord.

“Got it?” he asks.

The siren nods.

“All right. Take care. I’ll see you in a couple hours with more food.”

Sylvain grabs his sword and the key to his cabin, opens the door, and comes face to face with a worried Alois.

“... Good morning,” Sylvain says after a pause, pulling the door closed and locking it behind him. He raises an eyebrow at Alois. “Can I help you?”

“Let me see your eyes, boy,” the older man says, cupping Sylvain’s face gently in two hands. “I’m looking for the Thrall.”

“The what?”

“The siren’s Thrall. Their hypnotic magic. It turns your eyes gold like theirs.”

His siren’s eyes are orange, not gold. Sylvain cuts himself off from blurting that out just in time, and Alois releases him with a sigh.

“I’m just worried for you, Captain. Locked overnight with something that dangerous. A good fishman only takes what he needs from the ocean and returns the rest to it. Taking something like that—“

“ _Someone_.” Sylvain shoulders past his first mate with a scowl. “He’s not a thing. He’s a person. He understands human speech.”

Alois shakes his head. “You’re my Captain and my friend. But you’re underestimating this creature. I just hope you’re right, for all of our sakes.”

Fitting for the mood of the crew, the day is overcast and grey. They find a couple more schools of fish - Ignatz having mended the cuts Sylvain made in the net - and stock the hold with their catch. Sylvain brings the freshest one to the siren, who once again turns his back on Sylvain to eat. 

On a stretch of empty sea, just past midday, the bell in Sylvain’s cabin rings.

“Caspar, will you take the wheel?” he asks his crewman. The sailor salutes him, a leftover from his brief time in the military, and takes Sylvain’s place at the helm. He walks quickly back to his cabin in time for another ring, unlocks it and sees the siren once again on the floor.

He heaves a sigh and rolls his eyes. “You really don’t learn, do you?” he asks, striding across the floor to pick the siren up. Wiry arms wrap around his neck and tighten when he starts to put the siren back into the water, a cool forehead pressing against his cheek.

The siren hisses through his teeth.

“What’s wrong?” 

The siren draws himself up and closer to Sylvain’s body as Sylvain again tries to put him in the water, hissing.

Sylvain stands back up again. The siren relaxes. “Okay,” he says, adjusting his grip on the body in his arms. “Water bad. Um…”

He freezes as the siren pulls himself even closer, one arm wrapped around Sylvain’s neck. His hand flattens over Sylvain’s ear, then flaps like Sylvain had done to mime the fish the previous night.

“Hungry?”

The siren shakes his head. Once again, he flaps his hand over Sylvain’s ear.

The answer comes to him in a rush. “Your— your gills?”

The siren nods.

“You need fresh seawater?”

Another nod.

“Are you—“ fear washes away the brief exhilaration of understanding. “Are you dying?”

The siren shakes his head and blows a puff of air on the side of Sylvain’s neck. An electric thrill shoots up his spine; his arms go weak, and for a moment he almost drops the poor creature.

“Right,” he stammers, “okay, just— stay here,” and he lays the siren on his bed. “Breathe air. I’ll be right back.”

The image of the siren, pliant and exhausted in his bed, orange eyes soft with trust and understanding, burns in his head with every step. He dips his bucket in the tub, hauls it outside and tosses the contents overboard; five or six more times, trying not to steal glances at the shape wrapped in his blankets and watching him. Failing miserably at every trip and almost dropping the bucket when Ashe appears on the desk beside him.

“Need a hand?”

“What?” Sylvain colors. “No. Yes. I would— if you want to help me grab fresh seawater, you can.”

Ashe stares at him. Sylvain takes a breath and pulls himself together, flinging the dirty water over the side of the boat and along with it all of his uncomfortable feelings.

“Hey, Captain?” Ashe says, careful and uneasy.

Sylvain bites his tongue and minds his temper. “Yes?”

“You haven’t—“

A long, awful pause.

He knows what that silence means; knows the danger that comes with an affirmation and not a denial. Sylvain composes himself immediately and gives Ashe a cool look. “No. He is my guest. Not my bedfellow.”

Ashe’s green eyes sharpen. “But you’ve _thought_ about it.”

He knows. He won’t tell anyone, but he knows. It unnerves Sylvain like a knife at his throat, but he’s come much closer to death than this.

“Go get fresh seawater,” he replies smoothly, “or I’ll toss you overboard with the next bucketload.”

“Aye aye,” Ashe murmurs, following orders with a perfectly neutral expression. Sylvain can tell that he’s being laughed at. It’s better than being hated, at least.

Ashe leaves his buckets at the door like Linhardt had, leaving Sylvain to empty them in the tub. “Gonna keep me fit, doing this every day,” he grunts as he pours seawater in the tub. “I only bathe once a week myself, you know.”

He makes the mistake of looking back at his bed. The siren is there still, lying on his side, dark hair draped on Sylvain's bed. One blanket is draped over his hip, hiding most of his scaled tail from view. The siren’s cheek is pillowed on his elbow, his free hand blindly tracing the stitches on Sylvain’s quilt.

For a moment, Sylvain can’t breathe.

“Captain? Here’s more— oh, _saints and sails,_ it got out of the tub?!” Caspar drops his bucket - which somehow stays upright - and he charges into the cabin, drawing his sword. “Stay back and don’t look it in the eyes!”

Caspar charges in blindly; with his eyes closed, it’s easy for Sylvain to grab the much shorter man, picking him up to stop him dead. “Caspar! Stop it! I put him there!”

“Oh goddess, it’s _seduced_ you?”

Sylvain is sorely tempted to dunk Caspar in the half filled tub. “No, I put him there to be _comfortable_ while I got him clean seawater! Save your sword for pirates!”

He all but throws Caspar out of his quarters, locking the well-meaning but rambunctious man out. Sylvain bangs his head against the door for good measure.

“Why did I employ a crew of fools?” he asks the impassive woodwork. It offers no reply. 

Movement on the bed catches his eye. His siren had sat up during the commotion but is relaxing, lines of tension leaving his shoulders as he sighs.

“Sorry about that,” Sylvain laments. “They’re good men, I promise.”

The siren huffs and fixes him with a look. Sylvain breaks eye contact first, rubbing the back of his neck.

“Anyway, I’ll get you the rest of your water.”

He unlocks the door and opens it a crack. The coast is clear, and more buckets of water have arrived. They may be idiots and more than a healthy amount of superstitious, but they are good men. 

Once the last bucket has been added to the tub, he returns to the bed. “Come here,” and he reaches down as the siren reaches up. The body in his arms is light from malnutrition but the muscles in the arms that cling to him are still strong. Unnaturally so.

The siren probably could kill him, even like this. 

Sylvain eases the siren into the bathtub, wincing as the cool seawater soaks his shirt past the elbows. “There you go. That feel better?”

The siren settles into his container, but as Sylvain starts to stand up again his arm is grabbed by a pale, sharp nailed hand.

“Yes?”

The siren pulls Sylvain down, careful and gentle, his normally impassive face cast in an uneasy expression. Sylvain doesn’t fight the pull, watching the siren’s face carefully.

His hand stops a few inches above the siren’s rib cage. “I— I’m not sure what you’re trying to tell me.”

The siren lets out a shaking exhale, and then; he feels it. A faint current under the water. Sylvain stares, wide eyed, at the siren’s side, where the slits between his ribs have opened up and are fluttering with a steady rhythm.

“Your gills,” he whispered, entranced. “They’re— you’re incredible, you know that?”

His fingers, curious beyond his control, curl and stroke the delicate skin. The siren jerks in the bathtub, his nails sinking into Sylvain’s arm.

“Sorry, sorry, sorry,” he hurries, expecting to be bitten. Instead he’s just released and the siren slips deeper into the water until only his eyes remain above the surface.

Sylvain bites his lip. “I take it you’re done talking to me for the day, huh?”

The siren raises an eyebrow.

“You’ve got spirit. Good. Maybe you’ll recover yet.” With another grin, he flicks water at the siren’s face. “Enjoy your soak. I’ll see you tonight.”

He leaves with a wave over his shoulder and without glancing back. Behind him, the siren raises his head and opens his mouth.

The door shuts and locks between them. The siren settles back down, fingers tracing the scar on his throat and he ducks back under the water.

The basin reverberates like a bell from a single, thrumming note, and in the dark the water glows golden.


	3. Chapter 3

**Notes for the Chapter:**

> please look at this LOVELY art of Siren!Felix done by Aly! Thank you darling~
> 
> https://twitter.com/alykapedia/status/1269961837572796416?s=21

The next few days become a routine. Sylvain wakes up, talks at the siren as he gets dressed, and is immediately inspected for the Thrall by one of his crew members. He delivers a fish or two to the siren, eats with the rest of his crew and does whatever needs to be done that morning. A little past midday, he empties out the siren’s large tub and with the help of his crew fills it back up with clean seawater. And at night, fish for dinner for both of them and an exhausted, uneasy sleep.

On their fifth morning together, Sylvain pulls on his boots as he sings a sea shanty under his breath. “ _ So we'll sing blow the winds high-o, a roving I will go, I'll stay no more on Fodlan’s shore to hear the music play— _ “

He hums the next part of the chorus as he comes over to the siren’s tub, dropping to his knees to be on eye level with his guest.  One orange eye slides his way, pupil a vertical slit, and regards Sylvain with suspicion.

“I really should think about something to call you.  _ Siren _ comes off as rude. You don’t read or write, do you?”

The siren, leaning his back against the sloped end of the tub, shakes his head.

“Fair enough. I’ll give you a name myself, then. How about… Blue? Sapphire? Topaz?”

The siren bares his teeth and clicks them together; a hollow threat, but a threat none the less. Sylvain sticks his tongue out at the siren.

“All right, I get it.” He grins. “I’ll think of something good while I get your fish. So demanding.”

Standing, wincing at the soreness in his arms and back from all the extra carrying he’s been doing, Sylvain heads for the door to his cabin.

He whistles some more as he charts their course back to Fodlan, enjoying the sea breeze on his skin. His hold is filled with fish ready to be sold, the bite on his hand has healed to a semi circle of dots that shimmer a faint blue in the darkness and are invisible in daylight, when Ashe grabbed his face for his regular Thrall-check this morning he pretended to kiss him; life is good for Sylvain today.

Until he breaks the news about port to the siren at breakfast.

The siren bares his teeth and snarls as Sylvain tries to placate him, lowering the rough sketch of the coastal town he had drawn for the occasion. “I’m not going to let anyone see you, I promised, remember? You magic’d that much out of me.” He can’t help but sound a little bitter about that, because it still scares him. Worries him that he’s been Thralled after all, just in ways his crew can’t see. “But we need to sell this fish to survive, and the longer the stay out here the more likely it is that we’ll rot or get attacked by pirates.”

“I’ll lock the door to my cabin and make sure it’s guarded,” Sylvain continues. “I’ll be back by sundown and we shall leave first thing the following morning.”

Slowly, those bony shoulders lower; slowly, the fire in those orange eyes lessens to a candle glow. Sylvain lets out a breath in time with his siren. 

The worst part about the magic is that he still wants to help anyway. An ache of empathy so deep he doesn’t know if it was planted or grew there naturally, but he doesn’t have the will to rip it out.

“I’ll keep my word,” he murmurs. “Trust me.”

* * *

The tricky part is getting everyone else in on the plan.

Sylvain stands at the head of the dinner table and bangs his empty mug of ale on the table for attention. They’ve eaten their meager supper - fish stew with crumbled hard tack biscuits and the last of their shriveled root vegetables - and are as content as they’ll be until they make land tomorrow. 

“Someone is going to need to stay on the ship and make sure no one goes in my cabin when we dock in the morning,” he announces.

A groan of dread echoes through the room. 

“Does that mean someone isn’t going to get to go ashore?” asks Caspar, looking uneasy.

Sylvain hesitates. “Yes.”

“But it won’t be you who stays,” Ignatz observes. 

Sylvain raises his hands in pleading. “I assure you, it will be business only this trip. No bars. No women.”

To his surprise, Raphael raises his hand. “I’ll stay on the ship. I’m big and scary. I’ll keep people away.”

Yes, and tell everyone exactly what he’s guarding in the meantime. Sylvain takes a moment to phrase his next words very carefully. “I think you’ll be better suited helping Caspar and Ignatz unload and sell the fish. You are our strongest man.”

Raphael grins and flexes. Good. 

The next voice that speaks up is one he didn’t expect. “I’ll do it.”

Sylvain looks at Ashe. He’s known the silver haired man the longest out of his entire crew; out of everyone, they’ve clashed the most on ideals and business acumen. Ashe is smart, yes, but more than that he is kind. He knows what it is like to be at the bottom of the social order.

And he has proven for years that he can keep a secret.

“Thank you, Ashe. Anything I can get you in town as thanks?”

“More books, if you don’t mind.”

He nods. “I’ll see what I can do.”

Later, as the mess is cleared out, Sylvain hesitates outside his own cabin door. Out here, in the fresh night air, he can think a little more clearly.

It’s like how he used to haul water back at his childhood farm. Two loaded buckets balanced on a pole across his shoulders; every step carefully placed to match the rhythm of the waters movement, trying not to let anything splash out. His shoulders still ache from the memory of the yoke cutting into his flesh. It’s the same here, trying to work in tandem with his crew and his charge. Caught in the middle of two responsibilities.

“Goddess, don’t let me lose them all,” he whispers under his breath, and unlocks the door to his cabin.

* * *

The Nuvelle Peninsula is a hotspot for trading. Merchants from Brigid and Faerghus will venture out here, to the westernmost point of the continent, and sell their wares to the Adrestian citizens in one of the few neutral places in this half of the world. Authority is often lacking here, due to so many nations meeting on the same soil, which is both excellent and terrible for trading and selling. No rules mean more sales, but it also means more pirates and thieves.

Sylvain keeps his hand on the sword at his waist as he walks down one of the paths of the open air market, hoping it’s deterrent enough for anyone trying to steal the book under his elbow. His father tried to teach him fencing, but the lessons never stuck. He always thought it was stupid to cling to their nobility while in reality they were—

“Ah, you, sir, with the flame red hair,” rasps an old man with a gentle smile. “Yes, yes, come here. I sense a great burden on you.”

Internally, he rolls his eyes. Externally, he smiles and approaches the little stall. Pots of salves and bottles of tinctures pepper the shelves of the booth, smooth and glittering in turn like pearls and diamonds. “How astute of you,” he says with an easy expression. 

“Your hands must be sore from hauling nets and ropes all day. I have just the thing; a balm made from whipped seed butters and healing lavender oil.” He twists the lid off one of the little jars and holds it up for Sylvain to inspect. It looks soft and inviting enough, sweet scented as well. “I’ll show you. Give me your hand.”

He reaches out, fingers seeking Sylvain’s wrist.  Sylvain recoils from the touch, covering his bitten hand with the other one. The bite has healed but the mark, though faint, remains. 

“Ah, that’s all right. It wouldn’t be fair to ask for a free sample.” He watches the man inhale, no doubt ready for another spiel, and thinks quickly. “What about that one?” he asks, pointing to a highly ornate blue bottle locked behind a tiny glass door.

The merchants eyes widen. “Oh, you have good taste, my son,” and he opens the cabinet, cradling the bottle gently. “This is my most powerful curative. It’s imported from the far southern side of Fódlan, and is infused with magic.”

A week ago, Sylvain would have dismissed it as hogwash. Today, he rubs at the bite on his hand and leans in.

“I didn’t think there was much magic left in the world,” he says carefully.

“There isn’t, thanks to the Empress. But the very core of this world is embedded with it, and some

of the lands outside the Empire still celebrate the old ways. This,” and he holds the bottle between his thumb and his finger, “is made from mermaid tears.”

The noise of the market around them fades away.

“From what?” Sylvain asks.

“Mermaid tears. Mermaids have powerful magic; like the Manakete Saints and the Taguels, their very  being is enriched with it, and their bodies can be used for a wide variety of curatives and potions. Their tears  and their saliva are some of the most prized parts.”

He stares at the bottle, the hairs on the back of his neck prickling. Before he can say anything further, however, a hand claps on his shoulder.

“Captain.”

He looks up and over into the sleepy blue eyes of Linhardt.

“I believe you might be needed back on the ship.”

Linhardt points. Sure enough, at the end of the dock where his little unnamed ship is moored, three guards in red livery are standing on the deck.

His heart stills in his chest and drops like a stone.

“Yes. I imagine so,” Sylvain’s voice observes. “Excuse me, sir.”

“Tomas,” says the merchant.

“Tomas. Thank you.”

Sylvain doesn’t remember how he gets to the ship; doesn’t consciously paste that smile on his face but it’s there, like armor, as he ascends the plank.

They’re clustered around his cabin door, their body language sharp and irritated. To his credit, Ashe is standing firm, quiet and earnest.

“I don’t have the key,” Ashe says as Sylvain approaches, darting a look his way between two of the soldiers. “You’ll have to take my word for it.”

“You Faerghus simpletons,” says one of them, “just because you can trade here doesn’t mean you can—“

“Gentlemen,” Sylvain calls, spreading his arms wide, book held carefully in his hand. “I am the captain of this little vessel. What upsets you so?”

“We heard noises coming from this cabin. Your crewman here won’t let us search it.”

Sylvain slips between them and pats Ashe on the shoulder. “You mean he wouldn’t let you chop the door down with your axes. Not to worry. I have the key.”

He hands the book over to Ashe and fishes the key out of his pocket. As good as he is under pressure, the key clatters in the lock for a moment before he turns it. Sick to his stomach and smiling all the while, Sylvain opens the door.

There is a person sitting on the edge of a bronze claw foot tub, their dark hair loose and settling on their shoulders. Their skin is pale, almost translucent in places, and their legs are crossed demurely. Their hands grip the rim of the tub, the knuckles white. But their eyes are their most arresting feature;  a  shimmering, impossible gold.

Well. It appears that a siren’s magic isn’t limited to songs and promises.

Those eyes land on Sylvain,  pupils dilated round with fear, and a fingernail taps twice the side of the tub.  Right. There are more important things to deal with right now. Sylvain rallies and improvises a cover story.

“No one here but my lovely companion,” he says, shucking off his shirt and draping it over the siren’s shoulders, “whose bath you have interrupted. Are you satisfied?”

The soldier who had spoken before takes a step over the threshold; the siren’s eyes narrow fractionally. “Companion, you say?” he asks. “Is he from Dagda? He looks expensive.”

Golden eyes flicker back up to him, hypnotic in their beauty. His hand still hovering next to the siren’s face as he arranges the collar of his shirt over those starved shoulders, Sylvain takes a breath to steady himself. 

It doesn’t matter if it’s because of magic or not. He made a promise. He will do his best to keep it.

“He is,” Sylvain says, turning to face the guard and closing the distance between them. “But between you and me,” he whispers, “he isn’t worth the coin. If a  _ sample _ would buy your silence, I would be worth more for your money.”

He can feel the noose around his neck tighten but he keeps his smile on. Adrestia isn't Faergus;  these soldiers don’t know him from Ashe or Alois.

Sylvain flicks two golden coins into the soldier’s line of sight, shifting his weight onto one leg to accentuate the broadness of his shoulders compared to his hips.

“Dealer’s choice.”

The guard hums and looks the coins over.  More specifically, he looks at the bite on Sylvain’s hand.

Sylvain wets his lips with his tongue, drawing those eyes away, and wills himself not to break character. This, at least, is something he has practiced.

At last the guard speaks. “Hard to split two coins three ways,” he counters, raising an eyebrow. 

Sylvain bites the edges of his tongue and fishes out another from the pouch on his hip. The soldier takes all three, then turns to his men.

“All clear.”

They salute. Sylvain follows the leader to the door of his cabin, then looks out at  the crew members  gathered on the deck. Ashe, Linhardt, and Alois are standing there in the sunlight, tense and expectant.  The latter raises his eyebrows at Sylvain, silently asking how things went.

Despite his fear of the siren, even Alois cares. Relief sweeps over Sylvain, washing the nervous strength from his limbs and leaving a smile in its wake.

“As you were, Ashe,” he says, grabbing the handle of the door to stay upright. “Alois, will you make sure the rest of the crew gets back to the ship before midday?”

“Aye aye, Captain.”

“Thank you both,” and he means it;  more than he can express here, or maybe ever.  _ Thank you for trusting me, even into danger. Thank you for keeping an open mind.  _ For now, it will have to do.

Sylvain locks himself inside the cabin and collapses immediately; his back hitting the door as he slides down, legs buckling, hands shaking.

“Oh, Goddess,” he whispers. “That was awfully close.”

He grins at the floor, manic with fear and relief both, then knocks his head back against the door.

“Oh, fuck. Fuck fuck fuck.”

As he sits there, eyes closed as he tries to steady his breathing, he hears a soft thump. Then another. And another.

Sylvain cracks an eye open to watch the siren staggering across the cabin towards him. The hem of his borrowed shirt is just barely enough to clear his hips, but Sylvain doesn’t have time to look away before the siren is stumbling to a seat next to him, back pressed against the wall. He bares his teeth - the fangs aren’t as pronounced here, nor are the points to his ears - and winces in pain. A shudder rushes down his body, sparks of gold erupting from his skin in a wave that runs from the top of his head to the tips of his pale, delicate toes.

When the sparks fade, the siren is back to his tailed form, side gills fluttering as he gasps for breath. His head tilts, exhausted, to the side to look at Sylvain. And when he opens his eyes, they are orange again.

They’re almost the same shade as Sylvain’s hair. Fascinating.

“Nice work,” Sylvain croaks, and holds out his right hand.  “Didn’t know you had something like that up your sleeve. Chose the right time to show it off, though.”

The siren stares at the offered appendage, his brow furrowing. Sylvain shakes it a little.

“Give me your hand. No,” he bats the tentative left hand away and points to the siren’s right. “That one.”

Once his hand is raised enough, Sylvain clasps it in his, grinning as he leans over. “We did it. Good job.”

Still frowning, the siren tightens his grip on Sylvain’s hand. The redhead winces as his still-bruised mermaid mark is squeezed.

“Easy, easy. Not quite so hard.”

Immediately, the hand is dropped.

“It’s fine,” he assures the siren as he leans forward, picking himself up and turning around. “Come on. Let’s get you back in your tub.”

With a visible effort, the siren’s body shifts back into a fully human shape. He takes Sylvain’s hands and pulls himself upright as well, wobbling when he stands like a newborn foal.

Glittering golden eyes meet mahogany brown.

Together, they walk carefully across the cabin floor, holding onto each other for dear life. Sylvain murmurs encouragement under his breath, glancing down a couple of times to make sure there’s nothing to trip over. And exactly once do his eyes flit to the hem of the large, loose shirt, wondering what might be hiding under the white linen draped so delicately over that pale skin. He gets a flick to his forehead for that.

“Aye, sorry,” he makes a point of staring at the ceiling. “Just curious.”

His siren huffs.

He needs help getting into the tub, legs too long and slender and awkward to move right. They look nearly hairless, too. Smooth and—

Ceiling, ceiling, ceiling.

There’s a splash and a sigh, and when he looks down again the siren has shifted back to his original form. He looks exhausted, completely limp as he rests against the sloped end of the tub with his eyes closed.

“Hey,” Sylvain says, leaning over and resting his elbows on the rim of the tub. The siren cracks an eye. “I’ll get you the fattest fish for dinner tonight, okay, Blue?”

The sirens twists around in the water, one hand emerging to cup the back of Sylvain’s neck as he leans in. It can’t be a good sign that his instinct is to freeze and let the sharp fanged being lean up until his lips are nearly brushing Sylvain’s ear and—

“Felix.”

The word is rasped out, coaxed from a damaged voice like a note played on a fraying violin string. Sylvain forgets to breathe trying to memorize its music.

“My name. Felix.”

Cool fingers trail along the burning skin of Sylvain’s shoulder as the siren - as Felix - withdraws. He swallows, wincing, but doesn’t speak another word. Just watches Sylvain, the saturated white shirt flowing around him as pale and delicate as his tail fins.

Finally, Sylvain inhales. “Felix,” he repeats in a rush of air. “Felix, I— thank you.” 

And then, because he is nothing but a man of constant self sabotage, “I still think I like Blue.”

Felix flicks a drop of water at him, but it’s lacking real heat behind it and barely breaks the surface. The magic he’d used had left him pale and exhausted, but there’s still that flash of spirit in those sunset glow eyes. Sylvain can’t help but grin and flick water back, more effectively than Felix had.

Who knows if they would have continued without the knock at the door and Ashe’s voice calling for the captain? But the knock is heard, Sylvain stands, and after one last look (and a hastily pulled on spare shirt) he rejoins his crew on the deck in the sunlight, a flush lingering on his cheeks.


	4. Chapter 4

**Notes for the Chapter:**

> we... we have fanart again? please everyone feast your eyes on this LOVELY art of siren!Felix in Sylvain's shirt from the previous chapter. Thank you Meiikyuu! [[link]](https://twitter.com/meiikyuu/status/1276650901369954306)
> 
> https://twitter.com/meiikyuu/status/1276650901369954306?s=21

At the breakfast table three days later, Sylvain finds himself without an appetite. The fish that Raphael has cooked is fine as always, but the flesh is as unappealing and dry as ash in his mouth. The ale is tempting but a hangover at sea - familiar as it is after his usual shore leave - is not.

He’s been having nightmares again.

They fade by the time he wakes up, shimmering and vanishing like a coin dropped overboard. He can assume what they were about based on the pit in his stomach and the way his sleep-blurred eyes stick to the shadows that dance around his room, animated by the flickering oil lamp and the ceaseless rocking of the ship.

Sylvain has scars, too. Invisible ones, but no less real than anyone else’s. He might even deserve them.

“Hey, Captain?”

Sylvain looks up to see Ignatz and Raphael standing over him. Or wincing over him. Ignatz looks pale and nervous, and appears to be held upright entirely by Raphael’s hand on his narrow shoulder.

“Aye?”

“We were wondering— I was wondering,” Ignatz adjusts his glasses with a little trembling movement, “if, uh, the siren isn’t going to kill us if I could, uh—“

Raphael’s other hand claps on Ignatz’s shoulder and he leans over his friend. “Can we see it?” he asks, beaming.

Sylvain’s mouth opens, then closes as no words spring ready to his lips to respond. “Uh,” is his eloquent response.

“We won’t take long. I won’t slack on my duties,” Ignatz promises, “and I think my glasses might make me immune or at least resistant to its Thrall. They’re supposed to work their magic through music and eye contact and—“

“Enough,” Sylvain raises his hands. “You’ve won me over. Come along, then.”

He rises from the table, pushing his untouched breakfast in Caspar’s direction, and starts to head back to his cabin. The sounds of boots on timber floors confirms the Leicester natives are following him, and he knocks on the cabin door as he enters.

“Felix? I’ve brought guests.”

Standing in front of his crewmen and blocking the doorway, Sylvain is greeted with the sight of a legged, naked siren standing in the middle of his bedroom. Before he can process what he’s looking at, Felix jolts with shock, loses his form, and hits the deck with a slap of scales and solid muscle.

“Oh,” says Raphael, peering around Sylvain at the wet shape on the floor. “Is that normal?”

“Aye,” Sylvain grins, stepping forward to scoop Felix up in his arms. “Ignatz, Raphael,” and he spins around as he walks back to the tub, “meet Felix. Felix, these are my crewmen Ignatz,” he swivels his shoulders to point the siren’s tail at the slight man with large round glasses first, “and Raphael.”

The siren’s arm, which had wrapped around Sylvain’s shoulders to hold him close as he was carried, tightens. Fingernails sink into Sylvain’s bicep, and slitted eyes narrow.

“Should you really be holding it like that?” Raphael asks, looking distinctly uneasy. “It’s kind of bitey, right?”

“Eh, he’s not so bad once you get to know him.”

The siren clings tighter. Sylvain adjusts his grip on Felix, gritting his teeth at the weight - it’s a good thing to feel, he tells himself, it means that the siren isn’t starving to death anymore - and addresses the creature in his arms.

“Did you want me to put you down or not? They won’t hurt you.”

“It understands you?” asks Raphael.

“He does, mostly. Some words he doesn’t get, but—“

“Perhaps that’s your North Fodlan accent,” Ignatz concludes, expression serious as he takes a nervous step forward. “Hello?”

Felix hisses through his teeth. Ignatz stops dead and thankfully doesn’t reach for his sword.

For a moment, no one moves. Nothing moves, except for the bead of sweat that forms and slides down Sylvain’s forehead, coursing down his temple and skating across faint freckles to disburse along the ginger stubble at his jaw.

The siren jerks his head towards the bathtub. Sylvain carries him over, easing him into the water and kneeling behind the tub.

“Be nice,” he says to all persons present, and the look Felix shoots at him is pure insubordination.

“Did you say it was a he?” Ignatz is approaching again, hands held carefully away from his body with his palms out.

Sylvain rests his elbow on the tub, letting his fingers trail in the water a few inches from where Felix is hiding up to his chin. “Yeah. I think, at least. His name is Felix.”

“You named him?” Raphael asks. 

He pauses. So far, the ship has been amenable to Felix’s presence under the impression that he is mute and therefore largely powerless. It took them almost a full week to get this far with introductions, even. Best not to risk it.

“Aye,” Sylvain replies, “I figured a lucky name would suit a lucky siren.”

Felix tilts his head to the side just enough to steal a look up at Sylvain. He’s nervous, clearly. Strange for something so strong to be unnerved by the scrawniest sailor on board.

Ignatz lowers himself into a kneel a pace and a half away. “He looks healthier than he did when we first pulled him on board,” he says.

Sylvain feels his lips curl up in a relieved smile. “You think?”

“Maybe you should get him some weights or something to lift,” Raphael suggests. “My sis broke her leg once and when it finally healed it was all weak and skinny like him. She had to do stuff to build the muscle up again.”

“That’s… not a bad idea.” He gives the back of Felix’s head a considering look. “Might have him start by bailing out his own tub every morning. Save me the trouble.”

Ignatz pulls out a thin book and a small piece of charcoal. “Mind if I sketch him?”

“Do _you_ mind?” Sylvain directs the question back at Felix. Once he’s got the siren’s attention, he mimes drawing on his hand.

Felix turns his head and shoulders to more clearly emote frustration and bafflement at Sylvain.

“Don’t—“ Sylvain mocks Felix’s expression “— at me. _Can he draw you?”_

In response, Felix flicks water at Sylvain.

Raphael clears his throat. “Uh—“

“Shh,” Ignatz shushes. 

“Stop that,” Sylvain gripes. “I’m doing my best.”

Felix snorts, breaking eye contact to stare past Sylvain, tapping his finger on the tub. His jaw is set at an irritated angle, his dark brows furrowed.

And Sylvain gets it - if he can understand human speech, it’s likely he was able to speak it once. Sirens are supposed to be able to captivate people with their voices, after all. Losing that must have hurt, and be just as irritating for Felix as it is for Sylvain.

“What part confuses you?” he asks, softening his voice. “Draw?”

A shake of Felix’s head.

“He?”

A shake and an irritated look this time.

“Can?”

Felix nods, but with a little twist of his mouth that says it’s not the whole story.

“I’ll not make you do anything you don’t want to do, Blue,” Sylvain assures him.

Orange eyes snap to his face at that, an expression of vulnerability so sharp and so sudden that Sylvain forgets to breathe.

“Is it why I want to draw you?” Ignatz pipes up from a few feet away, shattering the moment. Felix jerks his head around to look at him and nods, slipping deeper into the tub but approaching the side closest to Ignatz.

Ignatz recoils, but is stopped by Raphael’s hand on his shoulder. He flicks a little smile up at his friend, then looks back at Felix. Or in Felix’s direction, at least. Sylvain doesn’t think either of them have made eye contact with the siren yet.

“Sirens are incredibly rare. I want to draw all the sights of Fodlan so I can share them with people who are less lucky and are not able to see the world for themselves.” He swallows. “You will probably be the only mermaid I ever see. May I?”

Felix narrows his eyes, then glances up one more time at Sylvain.

“Up to you,” he says. After a beat, he lowers his voice and adds for good measure; “I promise.”

Felix’s pupils dilate. His head snaps back around to stare down Ignatz, then with a wet slap the finned end of his tail emerges from the interior of the tub. The delicate fins flare out, water dripping down the long spines that support the translucent blue membrane to bead one by one and drip onto the cabin floor. 

His face, the lower half of which is still hidden by the rim of the tub, fixes Ignatz with a challenging look. A raised eyebrow, daring him to complain about how little of the siren’s body is visible.

Ignatz lets out a low whistle, flips to a new page in his book and starts drawing furiously.

“How about you, Raph?” Sylvain asks. “Any questions?”

“Nah,” his bosun beams. “I’m just here for support.”

“And you’re very good at that,” Ignatz assures him, eyes never leaving his work except to stare at Felix’s tail.

To his credit, Ignatz is a quick artist. Perhaps part of that is his own anxiety, but it can’t be much past five minutes before Ignatz stands and dusts the charcoal off his fingers. 

“Thank you,” he says, looking at Sylvain first and then in Felix’s general direction. “Both of you. Felix, you especially. You… really are incredible.”

Felix huffs through his nose.

“Feel better soon, okay?” Raphael adds, and Sylvain ushers all three of them out the door before the moment of peace is ruined.

“All right, all right, back to work.”

And as he closes the door, he gives Felix a grateful smile of his own.

* * *

“I think Raphael was right, you know,” Sylvain says to the siren later that night, as he’s preparing for bed. “You might feel a little better if you got some exercise.”

Felix is laying on his stomach in the tub, watching him as usual. The flick of his tail is more likely restless than nervous, but he’s still taken to stealing glances at the door as Sylvain takes off his coat and boots.

“Let’s see,” and Sylvain casts around his cabin, looking for things that the siren could use for weight training or something similar. At length, he spies the bare rafters that run along the roof of his cabin.

He discards his shirt and with a jump, he grabs the closest rafter and starts doing chin ups.

“Like this,” he pants, “you— use your body weight— to build the muscles in your arms.”

Sylvain glances down. Felix is watching him with intent, slitted eyes dark with interest. He can’t help but wink at the siren in his bathtub, and is rewarded with a snort as Felix looks away.

He drops to the cabin floor, flexing his hands to work out the pinched skin. “See what I mean?”

Felix shrugs.

Not satisfied with that dismissal, Sylvain goes to his knees again, taking up his usual spot along the rim of Felix’s tub.

“Thanks for being a good sport today,” he says, changing the subject. “I appreciate you not biting anyone.”

Another subdued reaction.

“You all right?”

This gets him a little more; a look over one narrow shoulder that lingers with consideration. Sylvain waits.

Felix sighs and lets his head rest along the sloped end of the tub, tilting it away from Sylvain. It’s not an obvious no, so Sylvain gets a little more comfortable and runs through the events of the day in his head.

In the end, he’d let Ignatz draw him, so that couldn’t have been it. Neither man is exactly the intimidating type, but he’d still been tense around them. Scared.

Felix shifts, and in the low light of the cabin at night the water on his skin highlights a wicked scar; one that goes deep and straight as an arrow.

No stitches on this one, though.

A thought occurs to him; a voice he’d forgotten in the wake of everything that happened that day. _Mermaid bodies can be used for a wide variety of curatives and potions. Their tears are some of the most prized parts._

“You’ve been around humans before,” he asks distantly, pulse roaring in his ears, “haven’t you?”

Felix twists around to look at him, tension climbing in his body, but he holds still as Sylvain dips a finger into the water and reaches up to his face.

From the inner corner of that frightened, cat-like eye, Sylvain draws a wet trail down his cheek, curving to trace around those parted lips just barely hiding sharpened teeth.

“They took your tears,” he murmurs, “and your blood, didn’t they?”

He hasn’t seen Felix move this fast since he was still tangled in the net. He doesn’t see it at all, actually; just feels the hand in his hair yanking him forward until their faces are inches apart.

_“No,”_ Felix snarls, his eyes burning with fury and his nails sinking into the back of Sylvain’s head. Not a denial; a refusal to ever let it happen again.

Sylvain closes his eyes against the sting of it, hissing at the memory of other crueler hands digging into his skin in years past. The cool metal pressing into his chest grounds him, and he focuses on that for one long breath before he opens his eyes.

Sylvain locks gazes with Felix, whose eyes are bright with pain and anger but still only orange, and speaks carefully.

“Okay.” 

Felix holds eye contact, his body shaking in the water, and slowly the hand in Sylvain’s hair relaxes.

“Okay,” Sylvain repeats. “You’re okay. I’m not going to hurt you.”

Gold rings those vertical pupils; but only for a moment, the magic aborted and dismissed before it can draw anything out of Sylvain. 

Felix’s hand withdraws, brushing along the edge of Sylvain’s ear as he pulls away, and of all the contact they’ve had before this is one that makes Sylvain shiver. The siren settles back down into the water, finally dropping eye contact to stare at the edge of the tub.

Sylvain clears his throat. “Should I be worried about someone coming after you?” he asks.

Felix looks up at him. A short, deliberate nod.

Sylvain returns the gesture and rises to his feet. “They’ll have to find us, first, and it's a big ocean. Rest assured, Felix,” and his lips curl into a grim smile as he stretches, “they’ll have to get through me to get to you. And I don’t die easily.”

His piece said, Sylvain walks back to his bed, licks the tips of his fingers and pinches the flame in the oil lamp out. As he slips under the covers, the familiar creak of the timbers rocking in the waves, another sound joins them. A soft rasping voice, struggling to hum a tune and faltering every other note. After a minute, with an irritated splash, it stops.

An idea drifts across Sylvain’s sleeping mind and melts seamlessly into the miasma of his dreams.


	5. Chapter 5

**Notes for the Chapter:**

> Sorry for the delay, but hey! this chapter is almost twice the length of all the others so that should help.
> 
> HUGE shout out to my beta Isa for cleaning up this chapter for me. You’re amazing, my friend!!!

Of all the men on his ship, Linhardt is the one Sylvain understands the least. He’s smart - probably the smartest of them all - but he’s quiet and careful and indolent in a way that doesn’t match the usual personality of a man making his wages through hard labor. The fact that he’s out on the ocean at all when he seems the type much more suited to studying in tall buildings overlooking the sea with a window cracked to let in the breeze baffles Sylvain.

And then he’ll see the way he looks when Caspar talks to him, coaxing out a more playful side, and Sylvain will hide a quiet grin of his own. Perhaps some things are worth running away from your comforts for.

“Hey, Linhardt,” he calls over the breakfast table in the meantime, waving the sailor down. “You still got that chunk of whale bone?”

Freshly relieved from a night shift, Linhardt yawns. “I do. I think.”

“Mind if I have it? I’ve got something in mind to make from it.”

“Sure. I’ll get it to you when I wake up.”

Before Sylvain can argue - not that he was inclined to fight anyway - the sailor vanishes into the crew’s sleeping quarters and closes the door behind him.

“Head up, Captain. Lemme see your eyes.”

He doesn’t bother hiding the dramatic roll to his eyes as he leans back in his chair, staring at Alois upside down. “It’s been over a week,” he gripes. “I think I’m safe.”

“All due respect, you don’t know what those things are like in a fight.” Alois lets go of Sylvain’s face and accepts a plate from Raphael, taking a seat at the table next to Sylvain.

“And you do?”

“Not the sirens. But I’ve seen the Manakete Saints in action, long ago.” He shivers. “Magical beasts aren’t to be messed with, for sure.”

“I’m hardly messing with him,” Sylvain defends himself, accidentally making eye contact with Ashe as the latter grabs a couple hard tack biscuits. But he’s had years to school his expression, and his face doesn’t falter under Ashe’s stare. 

“I’ve no intent to harm that creature,” Alois assures him, “but I’ll not sleep sound until it’s off this ship. And it eats too much.”

That much is true. Felix’s appetite has started to increase, and while he eats the whole carcass he consumes three times as much as most of the crew and twice as much as Raphael. Such a delicate body, and such a terrifying metabolism.

“Better the fish than us,” says Ashe, and returns back to the deck.

Two bites left of breakfast, and a bell rings out. A spike of unease jerks Sylvain to his feet, not quite running back to his cabin to unlock the door, and abruptly he comes face to face with Felix.

Legged, naked Felix with only a blanket clung to his chest for decency.

“Goddess have mercy,” Sylvain pleads skywards as he steps inside the cabin, only to be trapped against the door by Felix. He glances down into slitted, irritated orange eyes and doesn’t process the word hissed at him.

“Sorry?”

Felix swallows, rubs his throat and tries again.

“Bored,” he rasps, then points meaningfully over Sylvain’s shoulder.

“Cabin fever, huh?” He laughs, and Felix presses closer with another hiss. “All right, all right. I’m scared.” He’s not. But his heart is racing, so it’s close enough. “But we should probably put something on you. That’s a lot of skin you’re showing.”

Sylvain means to just gesture along Felix’s side, where the blanket doesn’t cover and leaves one leg entirely bare, but his fingertips stroke along the siren’s skin. All at once he is made aware of how it’s softer and smoother when Felix shapeshifts.

Painfully aware. 

He becomes even more aware that maybe he shouldn’t be touching a person who recently revealed they had been abused by humans for profit.

But Felix doesn’t flinch away, just rolls his eyes - a gesture he picked up from Sylvain himself - and starts to unbutton Sylvain’s shirt.

“Hey,” and his voice drops low on its own accord, “I need this shirt.” 

Felix flicks a glance at him. Sylvain clears his throat and sidesteps, walking quickly over to a trunk of clothes. His hand tingles where it touched Felix’s skin.

“Better not do pants just in case you shift back,” he narrates as he searches his belongings, “so a long coat would be—“

Sylvain’s fingers brush finely woven wool at the very bottom of the trunk, and  his mouth snaps shut. Slowly, he pulls out the dark blue coat and inspects it in the daylight seeping through his windows.

It’s a fine coat, darkened in a  couple spots with brown-red stains, with broad shoulders and quality buttons. Even with the shoulders and lapels bare of decoration, the cut is distinctly militaristic.

“This should be long enough,” he forces himself to say, turning to present it to Felix. “Here. Wear this.”

Together, they get Felix into the coat; together, they step outside of the cabin; and together they are reminded why the siren has been kept hidden away all this time.

“It got out!”

Cries of alarm split the morning air. Sylvain immediately puts himself between the siren and his well intentioned crew, even as Alois and Caspar draw swords.

“Easy, easy, he’s not going to—“

From behind him comes a wicked snarl.

Sylvain turns his head; he sees a terrifying creature, eyes wide and wholly golden, mouth too large for its skull and overflowing with shark-like teeth. It’s glaring past his shoulder at the crew, an awful noise burbling from his throat like a rabid dog with a crushed windpipe.

He hates that he knows what that sounds like.

But to his surprise, the siren doesn’t try to retreat. Instead, a clawed arm reaches out and shoves Sylvain back, as Felix positions himself  _ between  _ the crew and the captain.

“Oh,” Sylvain says, touched. “Oh, I get it. Okay. That’s sweet of you.”

Sylvain gives himself a moment to breathe, that tightrope feeling washing over him again. It’s okay, though. He’s very good at performing.

“Not that this isn’t very flattering, but everyone needs to relax. No one is in any danger here,” he assures them, keeping his tone even and his body language relaxed.

Alois gives him an incredulous look. “Did you hear that thing beside you? See it?”

He forces himself to reach out and cover Felix’s face with his hand, palming the siren away.  No fangs sink into Sylvain’s flesh, no bones are broken; Felix makes a disgruntled noise and yields, his face shifting back to normal. 

Sylvain can’t hide his smile. “What teeth? You just startled him is all.”

“We,” states Caspar, deadpan. “Startled him?”

“Did he come out with a sword?”

Caspar twists his mouth in a wry grin, then sheathes his weapon. “Fair enough, Captain.”

Ignatz and Ashe, a few steps behind Caspar, visibly relax and return to their previous tasks. Only Alois remains, lowering his sword with a look of such profound sadness that Sylvain nearly forgets the law of the sea: never ask where your comrades came from.

“Be careful, boy,” is all Alois says. “The greatest man I ever knew fell to a Manakete. Don’t want to see you make the same mistake.”

There’s nothing to say to that, so Sylvain keeps quiet as Alois retreats. The adrenaline of the moment fades and after another steadying breath he turns to face the siren again.

Felix’s golden eyes and monstrous teeth have smoothed back into normalcy. He’s scowling faintly as he watches the rest of the crew go about their business. When he catches Sylvain watching he drops his gaze, shifting uncomfortably under the woolen coat.

“Thank you for trying to protect me,” Sylvain says. “But they’re good people. All of them. They won’t hurt me or you.”

This gets those eyes back on him. And they’re not happy.

“Trust me,” he repeats. “I know them.” 

He leans in, lowering his voice. “And I won’t let anything happen to you.”

Felix heaves a sigh and steps around Sylvain, walking on cautious, unsteady feet to explore the rest of the deck.

With Sylvain acting as mediator and tour guide both, the rest of the morning goes rather smoothly. There are uneasy looks on all sides, of course, but no more weapons drawn. No more teeth bared. And the only person that pulls him aside is Ashe.

“You kept your coat all this time?” he asks, low and terse. Felix is being talked to - or talked at - by Raphael, who’s trying to teach him how to tie a complex knot.

“I had forgotten I had it,” Sylvain replies, voice barely above a whisper. “I stripped off as much of the military decoration as I could, but it was the only coat I had for an entire winter.”

“Better get rid of it. No one here will say anything, but if the boat gets searched by the Kingdom’s military—“

“I know.” Sylvain rubs his throat, assuring himself a noose is not yet around it. “I will.”

At that moment, Ignatz’s call of “shoal to the northeast!” ends the conversation. Sailors scurry into action, preparing the nets to be tossed with the hopes of snaring a good day’s catch.

Felix intercepts Sylvain on his way to his corner of the net, making flurried movements with his hands. Sylvain takes a deep breath, readying a fresh explanation.

“Right, okay, so these nets,” and Sylvain gestures to the tangled mess of ropes behind the siren, “get thrown overboard—“

He’s cut off by a hiss and another series of movements. Sylvain frowns, trying to make sense of Felix’s gestures.“I’m not sure what you’re doing. You’re— swimming into a wall?”

“Captain? The nets?” Caspar gives the pair of them an incredulous look, his hands already full of knots and rope.

Another dramatic huff and an eye roll, then Felix plants his hands on Sylvain’s shoulders. He presses down firmly, then points to himself, the ocean, and back to Sylvain before he cups Sylvain’s face in his hands.

The sudden intimacy robs Sylvain of his breath. Transfixed entirely by orange eyes that flicker like candleflame, he barely hears the whispered words.

“Trust me,” Felix mouths, a voiceless phrase, and shrugs off the coat. Before Sylvain can react, Felix dives overboard, shifting from human to merfolk in midair.

Underneath the surface, Felix rolls onto his back and repeats his flurried hand movements one more time, pointing to the school of fish up ahead. And finally, Sylvain understands.

“Ready the nets! Looks like our guest is gonna try to work for his supper!”

Sylvain instructs his crew with more confidence than he feels, as he’s done several times before. This time, it’s not poor weather or a lack of good schooling that’s putting doubt in his mind; it’s concern for the siren, out there in the deep. Felix is better than before, but even a siren has predators, right?

His introspection doesn’t last long. Within minutes, every crew member aboard is struggling to haul in the largest catch they’ve had in years. 

“Heave!” calls Alois, and as one they move.

“What did— the siren do?” Caspar grits out between mighty pulls.

“Scared the school— into the net— like a sheepdog—“

“A what?”

Sylvain hides a grin. “Heave!” he joins in, with voice and hands alike.

He watches the starboard railing approach the surface of the ocean as the boat tilts under the weight of the haul, and prays it doesn’t capsize. 

“Put your backs into it, men. Heave!” Sylvain bellows.

With a miraculous effort, they pull the catch onto the deck. Whoops and cheers erupt; they’ve caught more in one sweep than they usually net in a week. Sylvain cheers with the crew, but he hurries back to the side of the ship, searching the ocean. There’s no sign of the siren.

“Felix?” he calls, even as he knows he’ll never hear an answer. “Felix!”

He leans over, staring into the endless blue sea, and imagines it swallowing his reflection.

Felix had told him to stay. That’s what the press to his shoulders meant. And the pointing must have meant that he would return, right? What if he—

There’s a splash and a thunk from the other side of the ship. Sylvain sprints across the deck, leaping over a kneeling Caspar and a pile of fish, and throws himself against the rail.

Felix is clinging to the side of the ship. He looks exhausted, and the hand that reaches for Sylvain trembles.

It also doesn’t reach him. “Shit,” he curses. “Get me a rope, now!”

Time passes in an eternity of heartbeats before a sturdy rope is placed in his hands. Felix’s grip slips, and Sylvain nearly dives in after him, but Felix  flaps his tail and swims alongside the ship, slowly falling behind.

When the rope is finally tossed overboard, the siren swims for it in one last burst of energy and clings. Sylvain hauls him up so fast his hands burn, and maybe someone is helping, maybe his crew has gathered behind him to haul the siren up, but he can’t look or breathe until he’s reaching over the side and Felix’s arms are wrapped around his neck.

“There you are,” he murmurs, cradling the siren in his arms; scaled shoulders heave with every breath, limbs trembling with exhaustion. “There you go. You’re safe. You’re okay.”

Someone hands him the discarded coat. Draping the garment over Felix, Sylvain heads back to his quarters, oblivious to everything but the being in his arms. Felix growls the moment they cross the threshold, shoving at Sylvain, nearly getting dropped on the floor for his struggles, and huffs once he’s deposited back into his tub.

“What’s wrong?”

Felix snorts.

“Use your words,” Sylvain coaxes, just a little bit needling. “Or your hands in this case.”

A pause. Then the siren waves his hand in an arching motion, like a dolphin leaping through the waves, and then shakes the same hand in dismissal. Opens his mouth and points to his throat, then shakes his hand again.

_ Can’t swim. Can’t sing. _

“You’ll get the swimming back,” Sylvain promises him, taking his usual place on the floor, leaning on the edge of the tub. “Hell, you were great today. You just have to keep at it and you’ll build up your strength again.”

Felix bares his teeth in a snarl, but there’s not much anger behind it.

“I mean it. In no time at all, you’ll be back in that ocean and—“

Sylvain stops.

He’d avoided thinking about it until now; the ideal end to their tentative friendship. Felix belongs in the ocean, not in a brass bathtub, far away from humans and their nets.

He had promised, after all.

“Captain?” Someone knocks on the door to the cabin, their voice muffled.

It’s enough to break the moment, and Felix turns his head away. Exhaustion, dismissal, it’s difficult to tell what weighs him down against the sloped end of the bathtub, breathing slow and eyelids heavy. The scattered blue scales on his cheekbones and shoulders sit like frozen drops of rain on his pale skin, marked in a myriad of places with scars left by human blades and hands.

“I’ll leave the door unlocked for you,” is all he says, before returning to the world outside their cabin.

Golden eyes watch the door close.

——

Sylvain keeps himself busy on deck the rest of the day. He eats, laughs, and sweats alongside his crew and tries to convince himself he’s forgotten his epiphany from that morning. It works, to an extent, right up until Linhardt catches him at dinner.

“I want to see your siren,” Linhardt says, on his way to fetch a second helping - they did have a massive haul today - of stew for Caspar.

Spoonful of stew halfway to his lips, Sylvain pauses. “Is it urgent?” he asks.

“No. But tonight. Before you go to bed.”

Without another word, Linhardt whisks past him, ladling up the empty bowl and grabbing a biscuit for himself. He supposes it makes sense - since Linhardt is on the night watch this trip, he didn’t see Felix this morning. Perhaps he feels he’s missing out.

At the end of dinner, Sylvain leads Linhardt to his quarters. This time, he knocks first.

“Felix? It’s me. I brought someone who wants to meet you.”

He waits. After a couple seconds, he hears a gentle ring of the bell, and he lets both himself and Linhardt inside.

Felix is in his tub on his side, watching them approach. No teeth bared, no gleaming claws; good. “Hey,” he greets the siren, a little smile of relief stealing across his features. “This is—“

“Take this.”

Linhardt hands Sylvain a comb, walks past him, and collapses onto Sylvain’s bed.

A hiss sounds from the brass tub, and Sylvain turns around.

“What?”

Face up, eyes already closed, Linhardt dictates his commands. “Caspar said the fish thing helped you today, so he wanted to give it something. So I’m here to braid its hair so it can swim without getting hair in its face.”

A braid. Sylvain hasn’t done one in a while; he remembers braiding the mane and tail of horses in his youth, and once or twice later. The last time, the amount of mud and dried blood that clung to his hands after he finished had turned him off from it.

“How do you think you’re going to braid anything from my bed?” he asks in the present.

“Oh, I don’t intend to touch it,” Linhardt says, opening his eyes and turning his head to stare at Sylvain. “You’re going to do it for me. I’ll just tell you what to do.”

Rolling his eyes, Sylvain turns to address the siren. Felix is snarling at Linhardt, not the terrifying face he’d worn on the deck earlier but clearly furious. He meets Sylvain’s gaze and some of the tension in his body fades, especially as Sylvain approaches.

“Don’t worry. He’s harmless.”

Felix snorts but settles back into the tub. Sylvain kneels next to him and shows him the comb. 

“I’m gonna brush out your hair,” and he demonstrates on himself first. Felix doesn’t flinch when he starts to comb out the tangled ends of his long, dark hair, but Sylvain is careful not to yank anyway. “So what am I doing, Linhardt?”

“A five strand plait for sleeping,” and he yawns appropriately, “shouldn’t be too hard.”

It is, in fact, too hard.

Several long minutes later, phrases of  _ three under two and one, four over two, five over one  _ buzzing in his head, Sylvain regards the mess he’s made of Felix’s hair and groans.

“Linhardt,” he complains, “this is the most complicated thing I’ve ever tried to do, and I had Alois teach me how to tie sailing knots.”

Silence answers him. As Felix reaches up to feel the results of Sylvain’s labor, Sylvain turns to demand an answer from Linhardt—

who is passed out, blissfully asleep at the end of Sylvain’s bed.

“Should have seen that coming,” Sylvain mutters to himself. He starts to pull himself to his feet, but a hand yanks him back down.

Felix points to his hair. “Again,” he whispers, his sunset eyes burning. Impatiently, Felix undoes all of Sylvain’s hard work, separates a smaller section near his temple, and tries a braid of his own. It’s a little better than Sylvain’s, but not by much. “Again,” the shape of the word exhaled through eager lips, all breath and no voice, the best he can do.

Felix swivels around in the tub and presents the back of his head to Sylvain. Not the reaction Sylvain was expecting, considering the mess he made. 

“As you wish,” he murmurs, combing through Felix’s hair again. “I’ll just stick with a basic braid this time.”

Muscle memory takes over as he separates the hair into three parts; Felix’s hair is still smooth and damp, but this time the plait comes together as it should, tidy and even.

“I wanna ask you something, but since you need to keep your head still—“ Sylvain raps a knuckle on the side of the tub. “One rap for yes, two for no. Is that okay?”

Felix’s hand emerges from the water to give a decisive, metallic tap to the rim of the tub.

Sylvain rolls his questions around in his mouth like pearls, smoothing the edges off them. “Someone braided your hair before, right?”

One tap.

“You liked it?”

One tap.

“Okay. I’ll do my best.” He waits a heartbeat or two, aware of how relaxed the siren is, that beautiful tail arching over the opposite end of the tub. Hopefully he won’t destroy this moment for either of them. “Was it a human who braided your hair?”

A pause. Then, two taps.

“A siren?”

Another pause, this one longer. Felix pulls the end of his tail into the tub.

Holding the half finished braid in one hand, Sylvain strokes Felix’s shoulder with the other. “Hey. It’s okay. You don’t have to answer if you don’t—“

One tap.

Sylvain swallows, slowly resuming braiding. “Did they— were they captured too?”

Two taps, and Felix’s tail stirs the water with an impatient movement. Irritation, maybe. 

He has more questions. He always will. That’s the problem with Sylvain; he’s not easily satisfied. But pushing further has always led to trouble and Felix has been through enough today.

“There you go,” and he ties off the braid with one of the short laces from the neck of his shirt. He always leaves it open anyway. “I don’t have a mirror, but how’s it feel?”

Felix gingerly touches the back of his head and rolls over in the tub. They’re abruptly face to face; Sylvain blinks, focusing on Felix’s intense gaze as the siren glares at him. Or slightly above him.

“Well?”

In response, Felix runs his fingers through Sylvain’s hair, brow furrowed as he snorts through his nose. A gentle press to the side of Sylvain’s jaw turns his head, and then the siren is easing a lock of Sylvain’s hair separate from the rest and beginning a much smaller braid of his own.

Sylvain has always found it difficult to articulate what he wants. Part of it was his childhood, where his half brother spoiled anything Sylvain desired just to punish him for being born. Part of it was his adolescence, wasting away the hours with girls and hollow smiles. Sylvain’s wants have always conflicted with his needs, and so he denies having any desire at all.

He doesn’t have the right to want Felix, not after what has been done to him. Not after what Sylvain himself has done to other people. But it’s hard to ignore the feeling now, as pale-skinned knuckles graze his cheek.

Out of the corner of his eye, he studies Felix’s mouth. His lips look soft, tinted peach pink and parted. There’s no trace of the inch long fangs from before, no shadow of anger in that face. Only dedication to his task.

Thrall or no thrall, Sylvain craves Felix.

At last, Felix finishes the braid, letting out a heavy sigh and sinking into the tub. 

“Tired?” Sylvain croaks, half aware of his surroundings.

A tap as Felix lays on his back, sliding deeper into the water. Sylvain gets to his feet, shaking Linhardt awake and herding him out the door.

“Did that help?” Linhardt asks behind a yawn.

“It did something,” Sylvain mutters, closing and locking the door. He can’t get his boots off quickly enough before dimming the lanterns and rolling under the covers.

Only then, under blankets and darkness, does he let himself press his palm to his aching cock.

  
  



	6. Chapter 6

**Notes for the Chapter:**

> Thanks to Isa, as always. Just got home late last night from vacation to visit some family out of state, so I’m HELLA tired but! Here y’all go! Working hard on the next chapter already~
> 
> UPDATE: I TOTALLY forgot to link some bonus content and some fanart that’s occured this week! Please go show these artists some love, especially the FOUR PAGE COMIC GOOD LORD
> 
> Sylvain doing The Carry - https://twitter.com/nyarrancia/status/1308595151552438272?s=21
> 
> “They took your tears and your blood, didn’t they?” - https://twitter.com/4spiceblend/status/1287627365170819078?s=21
> 
> And for those of you hungry for Lore, here’s a google doc of some of the worldbuilding that I don’t think will make an appearance in canon/some talks about siren culture!  
> https://docs.google.com/document/d/1P5EfvfoQ_HT3KFFbvSFse_WOqs-i_Ovx9B4jkAwhsjE/edit

Sylvain wakes up early the next morning to a splash. He cracks open his eyes, rubs them for good measure, and sits up expecting to see a siren flopped on his bedroom floor again. Instead, he sees Felix clinging to one of the rafters, struggling for a grip before dropping back into the tub. He hits the rim on the way down with his shoulder, and the bell-like tone as bone strikes brass can’t feel good.

“Hey,” he starts, voice rough from sleep and rasping, “don’t do it like that. You’ll hurt yourself.”

The morning light filtering through the glazed windows is weak and grey with rain. Sylvain lights the oil lamp with a spark of flint, and the flame matches Felix’s eyes as he watches Sylvain approach. A few strands of dark hair have escaped the braid and are plastered to a pale forehead and scale-flecked cheeks, but the plait remains intact. Nothing to be proud over, but Sylvain is still warmed by the sight.

“If you want to exercise, do it over my bed.” He gestures over his shoulder to where the rafters continue, running perpendicular to the straw and cotton padded pallet. “That way you fall on something soft. Try to do it dry, though, okay? I don’t care to sleep on wet sheets.”

Felix dips his fingers in the water and flicks droplets at Sylvain’s face. There’s not a trace of pain in his movements; whether he’s good at healing or good at hiding it remains to be seen.

“I’m the Captain,” Sylvain grins back. “It’s my job to be bossy. Even to you.”

His eyes fall to Felix’s shoulder. In the gloom, it’s difficult to tell if a bruise is forming there or not. As his gaze lingers, the siren shifts in the tub, sinking beneath the surface of the water.

“You coming out to work with us this morning?” Sylvain asks, renewing his smile. “Sounds lovely and damp out there for you!”

Felix snorts, shaking his head. With his other arm, he shoves Sylvain towards the door to his cabin.

“Ugh, but it’s still early,” he complains, playing the part. “I could go back to sleep for another hour at least.”

At this, Felix slithers out of the tub, dripping as he shape shifts to walk the few paces over to Sylvain’s bed. For a long, heartstopping second, Sylvain can do nothing but watch him move on slender, muscular legs - until the siren, still visibly wet, shapeshifts back and flops onto Sylvain’s previously warm, dry and inviting sheets.

“You _bastard_ ,” Sylvain declares. Felix doesn’t so much as spare him a glance as he arches up to grasp the rafters again, pulling himself up on trembling arms and easing back down.

With a sigh of defeat, Sylvain dresses as best he can for the rain he can hear pouring down outside, and steps out into the downpour.

* * *

Guided by his compass, Sylvain leads the ship through the rain and to the nearest merchant harbor; Vakaria, a bright spot on the southern coast of Faergus. Normally he’d take a couple more days and aim for a port in Empire territory, but their hold is filled to bursting with fish and if they start to rot the smell will never come out of the old oaken timbers.

Hair still wet in places but drying in the afternoon sunlight, Sylvain grins at Ignatz’s shout of “land ho!” from the crows nest above. A clatter of movement follows, of the crew preparing for land and unloading their cargo, and as Sylvain surveys the ship with one hand on the wheel, his eyes land on a dusty blue military coat.

Pure terror shoots down his spine.

Sylvain deserts his post and staggers through the flurry of activity, numb with cold despite the early summer heat, and drags Felix back into his quarters. He slams the siren against the nearest wall, shaking hands undoing the catches on the horn buttons until Felix spins him around and pins him instead.

“What?” Felix rasps, the effort to speak painful, and Sylvain comes back to himself in horror.

“I— I’m sorry,” he holds up his hands. “I didn’t— I’m not going to hurt you.”

Felix rolls his eyes and snorts, and shoves Sylvain’s shoulders against the wall again. “What?” he repeats, and fixes Sylvain with a meaningful stare. 

Ah. That’s right. The siren isn’t so fragile and weak anymore; the hands that hold him still are like iron. He won’t be leaving without an explanation for his actions.

Sylvain looks past Felix to the open door of his cabin. “Close it,” he says. “I won’t move. Please close it.”

Felix’s gold eyes narrow but he says nothing, just walks across the cabin on long bare legs and closes the door. True to his word, Sylvain is still against the wall, and Felix slides into his personal space like he belongs there.

“What?” he asks again, a whisper this time, and Sylvain closes his eyes on a sigh.

“That coat,” he says, “belonged to an officer of the Faergus Royal Army. If you set foot wearing that on their soil, even without the old tassels and decoration, someone could recognize it. And you’d either be killed for killing an officer… or for being a deserter.”

With effort, he opens his eyes.

“I am the latter,” and Sylvain flashes a bitter smile. “I’m not a farmer, either. Just the lily livered son of Major Gautier, who inherited the title and left it behind to go sailing.”

Felix’s expression doesn’t break in horror like he feared, but his eyes narrow.

“Why?”

The question hits Sylvain like a storm-tossed icy wave. “Why?” he echos.

Felix nods.

“Because the only way you leave the military is if you die in it, or suffer an injury so bad it makes you useless.” He’d considered that, once, but hadn’t had the stomach to maim himself. “No one gets to walk away from his duty to his country.”

Felix shakes his head. “Why,” he asks again, urgent and voiceless.

Of all the questions he expected, this wasn’t one he’d ever prepared for.

“Why… why did I leave?”

Another nod.

This time, he laughs. “Because I’m a coward, of course. Why else would someone with military blood not want to fight?”

Finally, Felix snarls and grabs Sylvain’s arm; he doesn’t resist, waiting for a fatal blow. He wouldn’t blame the siren for it. No doubt the Royal Army has been complicit in acts of kidnapping and torture like Felix endured. Hell, he knows for a fact that Caspar and Linhardt have lost relatives to Faergus guns and blades in border disputes and old feuds.

But all Felix does is raise Sylvain’s hand and twist it to show the semi circle of blue marks in the skin. “No,” he whispers. “Not a coward.”

And Sylvain, all at once, remembers it as well; the day they met.

“I was tired,” he says, thinking not just of weary orange eyes but brown and blue and hazel, “of killing people just because I was told to do it. Just because someone else said I should hate them. I wanted to make my own decisions about whose life I should take.”

“Along the way, I found Ashe. He helped me get out of Faerghus, and joined my crew when I bought this ship. He’s the only person who knows…”

Across his face flickers a bitter smile. 

“... Aside from you. And you can’t tell anyone, can you.”

Sylvain’s expression fades into a blank mask as he waits for Felix to react.

That golden gaze is downcast, his brow furrowed in thought. Sylvain can see a hint of yellow light bouncing off his cheeks as he glances down. His eyes, when he’s using magic, aren’t just brilliant - they are luminous.

“Not a coward,” Felix whispers one more time, pressing Sylvain’s hand against his chest; and then he releases him to pluck open the buttons, one by one, down the front of the coat.

The moment he stands there, naked, in front of Sylvain is the longest second of Sylvain’s life.

But Felix isn’t affected in the same way, and he hands over the coat without a whisper of anything more than obedience to his movements. As he steps to the side, kneeling to rummage through Sylvain’s trunk of clothes for something else to wear, Sylvain stares at the closed cabin door.

“Yes, I am,” he murmurs, and doesn’t look away.

* * *

Dressed in Sylvain’s spare clothes and a pair of unusually tall boots, Felix helps as best he can with unloading the ship’s cargo. Sylvain slacks off accordingly, trying to teach him what to do and trying to tear his eyes away from him, and it takes the rest of the day to finish. As reward and apology both, Sylvain agrees to let them stay at port overnight.

No man is left behind this time; a couple of coins to the men on the docks ensure that no one will sail away on their ship while those so inclined to spend their time in town see the sights. This time, Sylvain himself makes sure to sport short black gloves to cover the mark on his hand before leaving the safety of the ship.

To Sylvain’s surprise, Felix accompanies him.

No sooner has Sylvain received his wages from the fishmonger for their load then he is being dragged away from the docks further inland to the town square. There’s a crowd there, of people milling about as they haggle with shopkeepers and eat and drink and laugh together; Felix’s complexion is pale and he flinches every time someone comes within arms length of him, but he doesn’t stop until they come face to face with a dais.

Sylvain, dreading the sight of a noose, looks up.

A band is playing music; a pair of fiddles, a flutist, and a brightly dressed dancer. The crowd has begun to clap to the rhythm set by the singer as she bounces back and forth, side to side like the points on a compass. Long silks swirl around her body, suspended in the air from the speed and grace of her movements.

But, as Sylvain glances to the side, she is not why Felix has dragged him here. Those eyes are fixed on the people behind her, and the hand around Sylvain’s wrist is so, so tight with desperate yearning.

How cruel of those mysterious captors, to have robbed Felix of the gift of song.

He watches the siren for a long moment, half expecting a tear to roll down those pale, smooth cheeks. Despite the pain written there, not a single drop beads in those glowing golden eyes. 

“You all right?” Sylvain asks at the end of the song, leaning in to be heard over the cheers of the crowd.

“What?” Felix spins around and whispers back, so close his lips are brushing Sylvain’s cheek as he shapes the word.

“You seem— upset.”

The siren shakes his head and releases Sylvain’s hand long enough to point at the people on the stage. “What,” he repeats louder this time, the rough edge of his voice coming in this time, and he sucks a sharp breath through his teeth at the end.

“Oh, the music? They’re playing instruments. They’re— devices that make sound when you do things with them.”

He casts his eyes about, searching for ways to demonstrate the concept, and sees a man empty a bottle of rum. “Here,” and with a charming smile, a coin and a quick request he buys the empty bottle. “Follow me.”

On the edge of the crowd, Sylvain blows air across the top of the bottle. The sound that comes out is low and steady and hardly what Sylvain would consider music, but Felix looks at him like he hung the moon.

“Want a try?”

He offers the bottle. Golden eyes flash and Felix accepts it with shaking hands, mimicking Sylvain’s actions from moments ago. The sound that plays isn’t as clear as before, but with a couple more tips Felix coaxes a steady note out of the bottle.

A hungry look crosses the siren’s expression, and his eyes light up like a struck match as he blows again. This time, the sound that comes out seems to be suspended in the air, heartbreaking and beautiful and terrifying at once. Sylvain feels himself pulled again, like he was weeks ago when Felix had forced their eyes to meet and he had made his promise to the siren.

_I swear to return you to the ocean alive._

The shattering of glass brings Sylvain back to the moment, and Felix staggers forward, the bottle in pieces on the ground. On reflex, Sylvain catches him.

“Felix?”

The siren guides Sylvain’s hand under his shirt, pressing it to his side. Through the tight gloves, he can feel the slits of his gills between his ribs. Felix mouths a request into his throat.

“The ship.”

When Felix pulls back, the golden light of his eyes is guttering, flicking between gold and orange. Whatever magic he has, he’s exhausted by maintaining a human shape for this long. 

Without another word, Sylvain scoops him up in his arms. “So drunk already?” he asks loudly, for the benefit of anyone listening. “I’ll take you home, darling.”

Felix is getting heavier to carry every day, but Sylvain bears him all the way back to the docks. Unbeknownst to either party, a pair of hooded brown eyes follow them aboard.

“Well, well. Not such a big ocean, after all.”

And the man grins behind his mug of beer.

  
  
  
  
  
  



	7. Chapter 7

**Notes for the Chapter:**

> so this is the Smut Chapter, which contains very little plot content. If you want to skip it, just go down to the scene break to arrive at the next morning.
> 
> For everyone here for monsterfucking - >:3

In his dreams, at least, he doesn’t have to smell the bodies.

He still crawls along those trenches, still hears the screams of the dying and the awful silence of the dead and feels the mud and the gore and the rain weighing down his clothes with every step, but at least he doesn’t have to deal with the scent, gunpowder and horse dung and sweat and blood.

This time, when he is shaken awake, he smells lamp oil and seawater.

Sylvain opens his eyes to Felix staring down at him, wet hands on his shoulders. A candle has been lit at his bedside, casting flickering light on them both. Sylvain’s throat feels raw and his forehead is clammy; he swallows.

“Sorry,” he croaks. Clears his throat and tries again. “Sorry, did I wake you?”

A twist of Felix’s mouth says that he did, but that’s not the question he is asking. Sylvain pretends he doesn’t notice.

“Ah, forgive me. Go back to sleep. I’ll be fine.” And he twists around to snuff out the lamp. 

Felix’s hands jump to his wrists and pin them to Sylvain’s pillow. He’s in human form - the tips of his ears are rounded, and the studded scales are missing from his shoulders. “You know,” Sylvain purrs, trying a different method to distract Felix, “this is an awfully suggestive position you’ve got me in. Are you trying to seduce me, Blue?”

Felix’s eyes widen. Blink. And finally narrow. He snorts and straddles Sylvain, leaning down so close that Sylvain’s breath catches in his throat. Despite his taunt, he didn’t actually expect Felix to—

Felix’s heavy tail dropping on top of him drives that held breath out of him, and Felix’s triumphant sneer is inhumanly sharp. Well and truly caught, Sylvain coughs.

“Fine. What?”

“The dream,” Felix whispers, still holding Sylvain’s wrists tight. Half of his face is bathed in warm firelight, the other cast in shadow. 

“It was a bad one. What more do you want?” Sylvain shrugs the best he can while pinned to his own bed, looking away from the siren. 

A pile of clothes past the foot of his bed looks like a corpse in the dim light. Sylvain swallows.

“It’s just a dream, anyway.”

The grip on one of his wrists tightens, and Felix yanks Sylvain’s chin back to face him..

“Mine, too. Talk.”

It takes him a moment to process the siren’s clipped speech. “Yours, too?”

Felix nods. “Talk,” he orders. “It helps.”

He settles himself onto Sylvain, relaxing his grip on Sylvain’s arm and propping his chin up, and—

It’s not like he wants to talk about it, but he does. He talks about how he can’t sleep without living the war in his dreams; he talks about the friends he lost and buried, sometimes in pieces and sometimes not at all; he talks about despite having almost three decades of memories to choose from, his sleeping mind returns to that hell.

“At least I made it out. So many people on either side didn’t. I guess I’m lucky.” Sylvain blinks up at the ceiling as he comes back to himself, and two things make themselves known to him.

One.

The weight on his chest is metaphorically gone, replaced with the somehow comforting crush of Felix’s body.

Two.

Somewhere along the line, he started playing with Felix’s hair.

Neither are things he wants to stop, so he takes another breath, then one more, and asks: “how did you know this would help?”

“A friend,” Felix murmurs, so soft Sylvain can barely hear him. “From there.”

“From your— from when you were captured?” He looks down at the siren, who nods. “Did they escape with you?”

At once, he knows it was a foolish question - how could anyone know Felix, save or be saved by Felix, and then let him leave? - but Felix just shakes his head.

“Dead, by now.”

“I’m so sorry, Felix.” Words fail him, and he struggles to recover. “I’m— I’m glad you’re alive, though. That you’re here. With me.”

Felix’s eyes, which had been lowered in quiet contemplation, flick to Sylvain’s face. “As am I,” he replies softly, his gaze traveling lower before he pulls himself up Sylvain’s body. The movement is sinuous, impossibly graceful, and it ends with Felix’s lips at Sylvain’s ear.

“I can help you sleep,” he whispers, close enough Sylvain can feel his lips shape the words, and a shudder travels down his entire body at the brush of skin on skin.

“Yeah?” His voice is rough, wrung out of tense vocal chords as his heart begins to race. “How so?”

Here, now, he knows the tension he’s felt between them hasn’t been one-sided delusion; here, now, the seduction in the air is definite and deliberate.

“You know how,” Felix breathes, stroking his fingers along Sylvain’s jaw.

Automatically, Sylvain tilts his head to the side, baring his throat for Felix. The siren’s hand comes to rest on Sylvain’s chest.

“Scared?”

“No,” Sylvain grins, biting his bottom lip. “If you wanted to kill me, you’d have done it by now. And hey,” he can’t resist, “if you killed me, that would stop the bad dreams too, so…”

Felix shakes his head; the movement is half a denial, half a nuzzle. “No killing,” he says. More disappointingly, another command follows after a beat of hesitation. “No kissing.”

“I can bear that.” He strokes Felix’s head, combing gently through the still-damp tresses with his fingers. “I’ve bedded women with worse demands.”

The edge of Felix’s teeth press, without catching, to Sylvain’s neck. “Not a woman,” he growls.

Sylvain lets his hand travel lower, down the spine studded with pointed scales. “I know. Believe me, I know.”

God, he’ll be ruined for anyone else after this.

The thought - of an after, of a time where his cabin is empty - chills him. To distract himself, he spreads his legs to settle Felix between them, the weight a satisfying pressure. His cock stirs, interest and heat pooling in the pit of his stomach.

“Thank the Goddess the crew isn’t aboard tonight,” he murmurs to the ceiling as he strokes his fingers along the slits of Felix’s gills.

As he’d suspected, they’re sensitive. Felix jolts against him, hissing a breath between his teeth; the way he presses closer assures Sylvain it’s pleasure, not pain, and he does it again to feel the siren squirm.

“Good?” he checks. A nod against the side of his neck, then another scrape of teeth. “Yes,” Sylvain encourages him, biting his own lip. “Harder. I like a bit of pain, you know.”

Felix sits up at that, holding himself over Sylvain to give him a heavy look.

“That surprises you?”

Without breaking eye contact, Felix shakes his head. A tint of a smile colors his mouth, and abruptly the terms seem unfair; there is little Sylvain wants in this life other than to kiss him. 

Not for the first time, not for the last, Sylvain swallows what he wants in favor of what he needs.

“Then why don’t you get back down here,” and he spreads his fingers out to stroke between all of Felix’s gills at once, “and show me everything you think you know about my preferences.”

Felix’s eyes go wide, the orange of his irises thinning to nothing as his slitted pupils dilate. The beauty and the horror of it both wash over Sylvain, but before he can move Felix dives in for his throat. 

In that second, he recalls that in the stories Alois tells, sirens eat people.

No teeth rend his flesh, no blood flows freely onto his pillow. Felix presses parted lips to Sylvain’s pulse and purrs; a voiceless vibration, a trilling tongue buzzing behind his sharp teeth. Something Sylvain has never heard nor felt before, but understands regardless. Affection.

“Yeah,” he rasps, his hips rolling against Felix’s tail through the sheets, “me too.”

Two sets of urgent hands work to strip away the fabric between them. Sheets and shirts alike are discarded, a few tears and loose threads in the weave. Sylvain bites his lip again to distract his mouth from trying to kiss Felix when the siren reaches between them and drags the tips of his fingers along his half-hard cock.

“Like this,” Sylvain croaks, showing Felix how to stroke him. How to grip just tight enough to slide the loose skin down the shaft, how to play with the slit at the head. 

“Yeah, yeah,” and he twists to press his face to the side of Felix’s neck, shivering with want. “Like that. Fuck.  _ Felix _ .”

At the sound of his name, the siren makes a breathy, needy noise and presses closer to Sylvain’s mouth. On a whim, Sylvain bites down - harder than Felix had, but with such blunt teeth he can only hope to leave dents that will fade in a couple hours.

Felix’s hand on his cock tightens then retreats as he rolls to the side, dragging Sylvain along with him until they’re parallel on the straw-padded mattress. Frantic, the siren paws at his own body, below the flat plane of his stomach to the scales that shine even in the shadow of Sylvain’s form. As Sylvain watches, a few scales retract and Felix’s questing fingers vanish inside him.

His mouth goes dry.

“Felix,” he starts, unable to articulate anything else - not allowed to say what he doesn’t want to mean, lips bound by the power of that first promise. He strokes along Felix’s ribs again to watch the siren’s body shake, the tendons in Felix’s hand flexing as he does  _ something _ between those eased-apart scales. “Felix,” he repeats, dumb for every other word, and he’s dragged in for another bite.

This one draws blood. He can feel it pierce his skin, smell that tang in the air, but no flashbacks yank him out of time to the nightmares long past. Instead, it’s soothed immediately by Felix’s tongue and another trilling, vibrating purr.

“How do you do that,” he marvels out loud, then chokes as Felix grabs his ass and hauls him closer. The head of his cock bobs against smooth, cool scales and smears precum along their jewel-toned surface. It’s an unusual sensation—

And then his mind goes blank as he’s pulled inside a hot, wet, tight opening.

Sylvain gasps like an untouched virgin, his hips jerking on their own accord as Felix draws him inside. It’s so much—  _ too  _ much— it’s almost painful in it’s perfection, silky soft and burning like melting wax and then it  _ tightens _ around him.

He doesn’t consciously wrap his arms around Felix and pull him closer, inching himself deeper into that intoxicating heat, but the way the siren shakes around him and mirrors his actions say it’s the right decision.

He almost makes it halfway inside before progress stops dead.

Sylvain forces his eyes open, blinking to focus them, and pulls his head back. Felix is trembling, his eyes almost closed and his breath coming in desperate, uneven puffs. It’s hard to tell in the dark, but the shadow of a blush is darkening his face and his heaving shoulders.

He has to clear his throat to get the words out, head spinning as Felix keeps clenching around him, stroking the sensitive head of his cock without so much as moving. “You—  _ fuck me, _ you all right?”

A nod.

Sylvain is very good at self restraint. Even he, however, has a limit. “Tell me if it hurts,” is all he can manage before he starts to thrust shallowly, in and out of Felix’s hole. 

Felix keens, a noise that peters out quickly, and rolls his body against Sylvain’s. His motion is more dramatic than his human partner, the latter handicapped by a much shorter spine, and Sylvain pops out with a vehement curse.

“So tight,” Sylvain murmurs as he guides himself in again. “Goddess, if you could have taken it all—“

Felix’s eyes snap open. He glances between them to where Sylvain has barely breached him, and licks the edge of his teeth. His glowing eyes are dramatic in the low light, and the feeling of something giving way inside Felix to take more of Sylvain’s cock nearly breaks him.

The look the siren gives him is pure defiant satisfaction. “Fuck,” Felix enunciates, eyes locked with Sylvain’s, and Thrall or not the reaction is immediate.

Life as a noble and then an officer has given Sylvain an advantage in life. Between his good look, his ample purse, and an attraction to all genders, he’s experienced things that other men twice his age may not have had the pleasure of knowing. Nothing in his life comes close to this.

Side by side, mis-matched and curved together like two puzzle pieces not meant to fit, Sylvain and Felix move as one. Bites and smeared half-kisses pepper shoulders and necks, hands travel over unfamiliar sides and backs, their pace reaching a fever pitch until Sylvain shoves Felix onto his back.

“You can take it, can’t you?” he demands as he picks up his pace, straddling Felix’s shimmering tail and taking in his disheveled expression in candlelight. The braid he’d weaved through that dark hair has long been pulled apart, and loops of hair flash blue and gold on his pillow. “You—  _ ngh _ , you want me like this.”

The siren nods, drawing Sylvain closer with clawed hands dragging down his back.

“You want me,” Sylvain repeats, the arms that hold him up above Felix shaking. Once more, the siren nods. It’s Sylvain’s turn to have something in him give, and he ducks down to break his only promise.

But his eager lips meet only Felix’s cheek.

The refusal stings, but it won’t kill him. The cuts on his back hurt worse and he welcomes those - they balance out the way that Felix can fuck him right back without moving, smooth muscles inside whatever Felix has shape-shifted to accommodate him stroking Sylvain to insanity. If it wasn’t for his need to pleasure Felix first, he would have come the moment he buried himself fully inside the siren.

He sets a quick pace, from necessity more than preference, trying to mimic Felix’s easy rolling motions. Unfocused, half open golden eyes meet Sylvain’s brown, and the siren gasps and writhes against the sheets with every movement. What he would have sounded like if those bastards hadn’t cut his vocal chords—

Well. He supposes it’s time to try to speak the siren’s language.

Sylvain kisses the stich-marked scar, there on his neck, and does his best to purr against Felix’s pulse like the siren did; presses parted lips against sweat-damp skin and trills his tongue through a sigh.

Felix’s back arches as he inhales, clawed hands sinking into Sylvain’s shoulders as he tightens around Sylvain’s cock, immobilizing them both. Throwing his head back in a silent scream, Felix trembles like a tree in a hurricane, bending and nearly breaking from the tension in his body. 

“I’ve got you,” Sylvain rasps, holding Felix close. The way the siren keeps clenching around him borders on the edge of painful and keeps him from coming. “I’ve got you.” For now, when he’d rather it be for good.

“Sylvain,” the siren pleads, a hot rush of fluid surging around Sylvain’s cock to flood the space between their bodies, “Syl—  _ Sylvain.” _

Fuck. He pulls away enough to check that he’s not hurt Felix - that it’s not blood coating his hips - and isn’t prepared for the sight of Felix’s milky release glimmering with candlelight over his pale blue scales.

If he doesn’t come in the next ten seconds, he thinks he’s going to die. But Felix is so tight, so incredibly tight, holding him close as wave after wave of pleasure wracks his body. He can’t move.

With a groan, he presses his mouth to the side of Felix’s neck again, stroking his fingers along his gill slits as he chants the siren’s name. “Felix, Felix, Felix,” a prayer like the ones his men would chant in the thick of battle, the last fragile bastion against insanity. “Felix, Felix, Felix.”

Breathing hard, Felix sags against the mattress, finally relaxing enough that Sylvain can pull out and finish. Just a couple of strokes of his own hand and a glance at Felix’s pleasured, hot face and he spills searing hot seed all over the siren’s belly and tail. Translucent white drops sit like pearls on the scales, smear like icing from a delicate confection on pale skin. It’s the most beautiful mess Sylvain’s ever made on a person, and yet he feels twice as wrecked as his partner. 

His back is raw from Felix’s desperate claws, so when he collapses he falls onto his side, staring at Felix in the lamplight. The siren tilts his head to follow the motion, eyes back to their usual orange yet still dark and soft.

“Clean you up,” Sylvain promises, “as soon as I can move.” He feels hollow and exhausted like a wound drained of poison. It takes everything in him to brush a strand of hair off Felix’s face.

Felix rolls onto his side, slowly, the corner of his mouth twitching in a wince. He brushes his fingertips, careful not to cut with his sharp nails, along Sylvain’s jawline. He blinks, and in the dark Sylvain thinks he sees a flash of gold in those slitted eyes.

“Sleep,” Felix whispers.

Like a candle snuffed out with a sigh, Sylvain is gone.

* * *

  
Sylvain wakes up to an empty bed and a heaviness to his body. Neither of these are unusual, nor are the bite marks he can feel on his neck or the scratches down his back, though the number and the depth is more than he usually sports after a night ashore with a lover. He sits up, stretches, and checks the tub at the other end of the cabin.

Felix is still asleep.

On careful feet, avoiding the creaky joints in the wooden floor that might give him away, Sylvain approaches the sleeping siren. There’s not a mark left on his pale skin, save the old scars, and his expression is lax. Charming, even, and Sylvain can see a little bit of drool in the corner of his parted mouth.

The braid they’d ruined the night before is still a tangle of black hair, adding to his untidy appearance. Sylvain kneels and brushes a strand of hair from Felix’s face. Orange eyes snap open, tension coiling through his body—

“It’s just me. You’re okay.” Sylvain holds up his hands.

Felix heaves a sigh and relaxes back into the tub, eyes falling half-shut into a sleepy, docile expression.

“Want me to brush out your hair and re-braid it?”

A single tap, and Felix arranges himself better in the tub to let Sylvain gather up his hair.

It can’t be more than a few minutes past dawn, but Sylvain works by touch instead of sight;

starting at the ends, feeling for the knots and taking his time with it all. Muscle memory takes hold and lets his mind wander, though it doesn’t go far from this moment, the two of them together. 

In the low, pale light, he presses a silent kiss to the crown of Felix’s head.

He finishes, dresses, and emerges onto the deck. A few steps away are the sleeping quarters of the crew, rows of hammock beds lining the walls and all of them empty. Save, however, for one object of interest.

The promised piece of whale bone sits by Linhardt’s bunk, pared with a whittling knife. It’s been a while since Sylvain indulged himself in the craft, but his previous idea springs to mind. He returns to the deck, both objects in hand, and sets himself to the task of relearning how to carve.

By the time the sun is high in the sky and Ashe and Alois find him, Sylvain’s short black gloves are dusted with shards of bone. 

“Captain?”

“Morning.” He waves. “Just working on a little personal project.”

The older man smiles. “Oh? How goes it?”

Not very well. “Just fine.”

Alois draws near to peer at the half-carved piece of bone. His expression tightens.

“A flute?”

“Maybe. Hopefully.” Sylvain shrugs. “Still haven’t worked out how to make it hollow, though.”

He can feel Alois staring at him, hear the cogs turning in his head. Sylvain doesn’t bother to deny or elaborate on his work; he is the captain, and it’s his choice what to do with his down time.

Ashe, however, changes the subject. “The rest of the crew should be along shortly. Raphael and Caspar are at breakfast, and I think Linhardt is still asleep.”

“Have a good night ashore?” Sylvain asks.

Ashe makes a point of nodding at Sylvain’s shoulder. “Aye, but perhaps a little calmer one than you had.”

That gets Alois’s attention away from the bone flute, and Sylvain’s cheeks to flush.

“By the bones of the Saints,” Alois swears, “that’s a bite! Are you all right?”

“Oh, aye,” and Sylvain rallies, falling easily into the story he’d crafted earlier of half-truths and careful omissions, whittling with the self assurance of a habitual liar. “I simply woke our siren guest up and got a bit of a nip for my troubles. It doesn’t even sting now.”

The look Ashe gives him is as dry and flat as paper, but Alois shakes his head gravely.

“Just hope that beast keeps to a fish diet,” the man states, “and doesn’t develop a taste for seamen.”

Sylvain fumbles the knife and cuts himself in the thigh.

  
  



	8. Chapter 8

**Notes for the Chapter:**

> Lots of art in this chapter! (And also lots of pain, oops)
> 
> We have a LOVELY cover art done by Lois! (The English major in me who spent an entire semester learning about the classic art of manuscript making and the illuminated art process is DELIGHTED) - https://twitter.com/lv2nt/status/1325087774538674176?s=21
> 
> and yours truly has replicated Ignatz’s sketch in the body of the text~

When Ashe takes the ship’s wheel for the night shift, Sylvain sits by a lantern at the stern and whittles at the piece of whale bone. He’s got the basic shape, but it’s refusing to hollow out nicely. He twists the knife, trying to spin it like an auger; brittle, the bone flakes and snaps at the end, ruining two days of work in an instant.

With a flick of his wrist, Sylvain drives the knife into the ship’s timbers. “Fuck.”

“Captain?”

At the edge of the lantern’s glow stands Alois, his hands behind his back.

“Aye?” Sylvain murmurs, sweeping slivers of bone off his pants.

“You’re making that for the siren, aren’t you.” There’s no uncertainty in Alois’s voice, no judgement. Nothing at all.

Uneasy, Sylvain puts on his best smile. “What, and risk him Thralling the whole ship? Nah.”

Alois sighs, his gaze dropping before he raises his head. In a moment, his posture transforms; a battle-hardened mercenary captain stands before him. “There’s no need to lie to us. We’re your crew, and we will follow your orders.”

“You don’t have to,” Sylvain replies on instinct, too galled by the memory of youth thrown away in the name of loyalty to hear it aimed at him.

“That’s why we obey them, Captain.” He steps forward, takes Sylvain by the wrist, and places something smooth in his hand. “Because we believe you.”

Alois retreats, and the lamplight flashes along a glass flute. Long, delicate, with swirls of red iridescence along its golden form, Sylvain feels the value of it at once.

“Before I joined your crew,” Alois says slowly - painfully - “I knew a man named Jeralt. He fell in love with a woman with pale green hair and a beautiful smile. This flute was her token of love to him, and was forged in dragon fire.”

Sylvain tears his eyes away from the flute. “You can’t give this to me,” he croaks. “Do— do you know how much this is worth?”

“I do. But I could never play it, and never sell it. It deserves to go to someone who needs it.” Alois gives himself a shake and laughs. “Besides, it was made from magic. Feels only fitting to give it to a creature of the same cloth, right?”

When Sylvain doesn’t answer, Alois lets the chuckle peter out. “Good night, Captain,” he says, and vanishes into the crew’s quarters.

As if under a Thrall himself, Sylvain stares at the space where Alois had just stood and wonders at the whim of fate to bless him with a crew like this one.

* * *

Sylvain keeps the flute hidden in his bedroom for a couple of days. He tells himself that he wants to give Alois the opportunity to change his mind and take back the priceless memory of his friend. Sylvain’s a good liar, but not even he can swallow that one.

The moment he gives Felix the flute, Felix will leave. It’s the only thing he needs to survive on his own. The gift of song.

At dawn on the third day, when he wakes to find Felix already on deck, Sylvain watches him from his cabin doorway. His shoulder pressed against the salt-washed wood, all but one of the lanterns burned out as the sun slowly rises, Sylvain tries to memorize the siren’s silhouette as he stares out at the horizon.

_You’re not a coward._

Sylvain ducks back inside his cabin to throw on a coat. He emerges and throws a salute to Linhardt, who returns it and shuffles back to the crew’s quarters. With one last bracing breath, Sylvain approaches Felix.

“Couldn’t sleep?”

Felix nods, eyes still fixed on the ocean. He’s in Sylvain’s shirt and the tall boots he favors, and not even that pale strip of exposed thigh between leather and linen can lift Sylvain’s spirits.

“You miss it.”

Another nod.

Sylvain has faced a lot of frightening things in his life; made painful decisions in the face of certain death and tried to save what lives he could. The stakes here are so much lower. He knows they are.

“You’re leaving, aren’t you?”

Orange eyes flick his way, Felix’s expression steady. Empty. Like the day they first met.

It would be easy to keep Felix around. His strength grows with each passing day, the muscles in his arms and back filling out from his work herding fish into their nets. The crew has gotten used to the sight of him on deck, including him in their conversations; occasionally, even, Felix will initiate with a gesture. They travel along the Adrestian coast, their hold overflowing with each catch. The mood of the entire ship is light with such easy coin.

And yet. 

Sylvain leans on the rail next to him, staring out at the ocean. The sea is so calm and inviting, even he would be tempted to jump in. “I’m not going to stop you,” he offers, keeping his tone light. “But I think you might want this.”

Smile still affixed to his cheeks, Sylvain places his fingers on the flute, raises it to his lips, and blows. Three notes spill out into the dawn.

Eyes like the early morning sun widen and blaze.

“Take this with you,” Sylvain says, “to replace what they took. And know that...”

Things he wants. Things he needs. They sit heavy on his tongue, and in the end he swallows them in favor for what Felix needs.

“Know that you will be missed.”

He passes Felix the flute and watches the siren mimic his movements; the glass flute glows like flame in the rosy sunlight. A single note peels out, clear and strong, as Felix raises it and blows.

All Sylvain wants is a kiss. Just one last tender touch to sate him until he returns to land and can drink away the memory of what he let go. As Felix lowers the flute, he leans in.

And stops.

Two clawed fingers press against Sylvain’s mouth. Slitted golden eyes reflect the rising sun.

“You promised,” Felix whispers.

He’s made a lot of promises in his life; to his parents, to women he meets at bars, to commanding officers. Most of them he’s broken, intentionally or not. This one he’ll keep, even if it breaks him.

And as Felix steps away, flute in hand, and dives soundlessly over the side of the ship, Sylvain feels something fragile in him crumble.

* * *

The first rule of the sea is not to ask personal questions. The ocean is full of secrets, both above and below the waves; everyone out here is running from something. No one asks where Felix went, or why Sylvain’s not eating much at mealtimes anymore.

A sheet of paper appears on Sylvain’s bed, a rough charcoal sketch of Felix in the bathtub bickering with Sylvain. He presses his lips to the paper, eyes closed tight as the memory sears through his mind, and tucks it away in his desk. He’ll have to find a way to thank Ignatz for this. To thank everyone.

Days stretch on, elastic and infinite, blurring into each other as Sylvain goes through the motions of his job. Wake, eat, read sea charts and tweak their course, cast their nets if they’re lucky, eat, sleep, repeat. Over and over along the Adrestian coast until near two weeks have passed without a trace of a siren anywhere.

“I can take the night watch,” he tells Linhardt. He’s not going to sleep well, anyway; he always spends too long staring at the empty bathtub in the middle of the room, half filled with seawater just in case.

“Suits me just fine. Ring if you need us.” Linhardt yawns and follows Caspar to the crew’s sleeping quarters, catching his hand as they fall into step.

The knife in Sylvain’s chest twists and he turns away, one hand on the ship’s wheel as he faces the horizon. He’s been through worse than this. He will overcome it.

Above him, the endless sky bleeds out the warm light of day, fading from pink to purple to deepest blue. A lone ship appears on the horizon where the sun had sunk down. One by one, the stars of the evening appear, countless and dazzling pinpricks of pale light that offset the warm glow of the oil lanterns illuminating the deck. The stars are never as vivid on land, and normally Sylvain would map the constellations he so often read about in his youth; Reyson and Naesala the twin cranes, Ninian the oracle, Panne the swift beast, Seliphe the cavalier. 

Tonight, he keeps his eyes on the waves and the ripple-broken facsimile of the night sky. The only thing he longs to see swims somewhere below them, after all.

Some time past midnight, Sylvain’s attention is drawn to the ship from before, looming ever larger. A two masted vessel is too big to be a pirate ship, or so he hopes. But it’s following them. And it’s gaining on them.

Sylvain steps back and rings the ship’s bell twice, unease stirring in the pit of his stomach. Ignatz and Raphael are the first out, and he sets the latter on raising all the sails. 

Ignatz scales the mast, clambering into the crows nest. “No signs of any nation’s colors, Captain!”

Trepidation slides into grim anticipation. He rings the bell again, raising the alarm. The crew stumbles on deck, bleary eyed but attentive, and his military training comes back to him in a rush.

“We’ve got someone unknown on our tail. Pile on all sails!”

“Aye, Captain, aye!” comes the immediate chorus, and Sylvain feels a rush of gratitude for his crew. He only hopes his instincts are wrong.

They’ve not caught a full haul yet on this trip.The tanks in the hold are stocked with more ice and water than fish, and he sends Caspar down to drain them. His ship is lighter, and with luck and a fair wind they might outrun whoever sees fit to chase a small, poor fishing vessel only crewed by half a dozen men. No pirate would bother them, it has to be— someone else.

_Should I be worried about someone coming after you?_

“Fuck,” he whispers to himself, spinning the ships wheel. Felix may be safe, but he can’t let his actions put his men in danger. Not again. Never again.

More than ever, Sylvain hopes he can do enough - to be enough - to save the lives of those who put their trust in him.

With every sail piled on and taut in the wind, their fishing boat skims the waves like the stones he would skip in his youth. In his gloved hands the wheel spins, guiding the craft away from the unmarked vessel. He murmurs a prayer to the Goddess and all her countless Saints that it might veer away and continue on its own path.

But like a cloud shadow passing over the land, the pursuant ship continues. And it gains on them, slowly but inexorably. There’s a flash of light, then an eerie thud, and a cannon ball erupts into the waves half a league from the ship.

“To oars!” he commands, sweat breaking out on his skin.

Seldom do they need to break out the long, flat-ended paddles; mostly they are used to navigate through reefs or around a rocky islet. Now, all but Sylvain and Ignatz haul out the oars, plunging them into the waves to row. If they’re caught, there won’t be much of a fight; a ship that size has to have four times his crew, at the least. If they’re caught, the game will be up.

He can hear them now, a faint murmur across the waves. Pirates, privateers, it makes no difference. They’ll be just as dead to those blades as they would be if the Empress herself wielded them.

Sylvain closes his eyes, memorizing the feeling of this moment; the saline tang of the ocean, the groan of taut rope and canvas, the breathless chants of “Heave! Heave!” from his faithful crew. If this is his last moment on earth, he will savor it. If Felix is the only life he could save, in all his years under this sun, then he hopes it will be enough to soothe the hellfire that awaits a killer like him in the next world.

And that is when he feels it; a stillness like a deep breath before a plunge. The silence of an ebbing wind, and the promise of a stronger one to follow. If they can catch it, it will carry them to safety.

Sylvain grits his teeth and calls again. “The wind is changing! Hard left!”

Alois and Caspar raise their oars. With a frantic spin of the wheel, Sylvain pivots the fishing ship on the crest of a wave. As Linhardt and Raphael dig in, the sails flag then flare on a massive gust of wind.

Like a bird, the sailing ship glides across the water, swift and sure. Behind them, the larger ship slows. Unable to adapt to the changing wind, it sits in the water, helpless to do anything but watch.

A cheer arises from the exhausted crew. Ignatz in the crows nest, Sylvain at the wheel, and the rest of the men on the deck allow a spark of hope to flare, warm and brilliant, in the waning night.

Like a thunderbolt, the cannonball shatters the mast, spraying splinters like hail on the men below. Ignatz screams and Sylvain is helpless to watch him flung overboard, disappearing under the ink-dark waves.

“Ignatz!” 

The scream rends the air, twice as painful as the cannon blast, as Raphael sprints to the railing to where Ignatz had fallen. With tear-glassed eyes, he turns to Sylvain, pleading.

If he turns the ship around now, they’ll be rammed. There will be no escape for any of them. The mast is damaged but the sail is still, by a miracle, catching the wind. They might make it out alive if they leave him behind.

They’ll follow him if he asks them. To whatever end.

Sylvain digs in his heels and spins the wheel, locking it into place with his bent knee.

The effort of turning makes the entire ship creak and groan, but it turns; as obedient and flexible as the crew aboard it, it yields to Sylvain’s will. A rope around his waist, Raphael leaps overboard as the other ship nears. It’s a rugged vessel, studded with long guns and damaged carvings of beasts and beauties alike. It would have been a beautiful ship once, and it glances to the side to run parallel the damaged sailing vessel.

Sylvain draws his sword.

“Alois,” he orders with steady steel in both hand and voice, “man the rope and make sure Raphael gets back on board.”

The first grappling hook soars through the air, scuttling across the timbers of the deck until it sinks into the railing.

“Ashe, Caspar, Linhardt. Guard him.”

And as a woman swings across the gap between their ships, her scarlet hair flashing like freshly-spilt blood in the lantern light, Sylvain knows this is where he stops running.

“You must be the captain,” she smiles - her eyes match her hair but not her expression, and the overall effect is unsettling. “I’ve been asked to take you alive.”

“By who?”

“Our captain.” This time, amusement glitters in her eyes as more of her crew mates swing aboard. Sylvain doesn’t break eye contact, a thin smile of his own playing across his lips.

And then he sees him.

Like a shadow, like a mangled copy, Sylvain’s brother lands on the deck. A privateer’s coat hangs heavy on his broad shoulders, and a thick ropy scar bisects his face from right eyebrow to left cheek. It stays immobile as he grins.

“Well, well. We meet again, little brother.” He cracks his knuckles. “Do you remember me?”

He remembers those hands on him; shoving and hitting and forcing him underwater. “Miklan,” he swallows, his usual calm cracking.

“Ah, good. You do. Tired of playing soldier and decided to play sailor for a bit?”

There’s a shifting behind him. “What are you talking about?” Caspar asks. “He’s not a soldier.”

Miklan’s grin shifts into a sneer. “You lied to them as well? Figures. It was the only thing you were ever good at as a child.”

Sylvain’s smile has flaws in it, cracks in ice ready to submerge him in cold terror. “What do you want?”

The red haired woman sneers. “You took something that belongs to us,” she coos, a cruel imitation of song. “What a naughty little boy.”

They know.

“Where is the siren?” Miklan asks, and were it anyone else Sylvain would have been fine; would have played it off, would have sent them away with urgent promises and empty words, would have come up with something. Anything.

But it’s Miklan, and suddenly Sylvain is not the captain of a little ship of runaways anymore, or a deserter, or the heir of a decorated military officer. He’s just a little boy, facing down the big brother he loved so dearly once, and he can’t lie.

“Gone.”

Miklan’s eyes narrow. “Search the ship,” he orders, his eyes never leaving Sylvain’s face. They stare each other down, silent and unmoving under the star-flecked sky. To the right, Sylvain hears water splashing and the gasp of a man catching his breath.

“We made it,” chokes Raphael. “Alois, help him—“

“I got him, I got him.”

“Ignatz?” Sylvain calls, still not looking away.

Alois answers. “Aye, Captain. He lives. Stunned I think, but he’s in one piece.”

Miklan raises an eyebrow. “For now,” he murmurs, low enough no one else could hear, and Sylvain bites the inside of his cheek to keep his expression steady.

Another long minute passes, then the thud of unfamiliar boots on the wooden deck. “No sign of the siren, sir,” someone says. “Only this.”

And that’s when Sylvain makes his last mistake.

He turns to look at the piece of paper held up by the privateer and his heart sinks into his boots. The charcoal-smeared image of the siren in Sylvain’s bathtub and the smile on Sylvain’s sketched face says enough.

“Ah,” hums Miklan. 

His hand snaps around Sylvain’s wrist, a grip so tight he can feel his bones grind, and Miklan presses his thumb into the tendons. The sword drops from Sylvain’s hand and he thinks, foolishly, that it’s the worst of his problems. And then Miklan peels the glove off his hand.

Like the constellations above, the mermaid mark on Sylvain’s hand glows.

“We only need the one,” Miklan says. Someone grabs Sylvain’s other arm and holds it out, and then—

The pain hits him first; the cold bite of steel and the agony accompanies the following rush of blood. The lightness hits next, throwing off his center of gravity so he stumbles when he is released, swaying on the deck like a newborn foal. And then the horror, as he sees not one but two gloves on the deck of his ship, one of them in a little pool of blood.

Then someone is grabbing him, lifting him. The world spins as he watches Miklan toss his glove - not his glove, his left hand - into the ocean. The last thing he hears before he passes out is the blast of a cannon.

“Felix,” he gasps as the world goes dark. 

_Don’t follow me._

  
  



	9. Chapter 9

**Notes for the Chapter:**

> And here it is! The final chapter!
> 
> I can’t begin to describe how thankful I am at the reception this piece has gotten. Considering how silly it’s origins, I really wasn’t expecting that it would become such a big endeavor. I will admit, this year was a rough one and it was difficult at times to keep going. But just knowing that I was making some thing that people liked, some thing that only I could do, kept me going.
> 
> I hope you can keep going, too.
> 
> Fanart at the end of the chapter - and I’ll keep adding links to any new pieces, too. I love you guys so much. Have fun!

There are two clear times in Felix’s life; Before, and After.

Before he was taken, he slept in a reef with his family. A little colony of mer-folk in the cold Faerghus ocean, no more than half a dozen in number. He’s on the opposite end of the world, now. But that’s not the only reason he doesn’t try to return.

The mermaid mark he left on Sylvain itches in the back of his mind, reminding him of unfinished business. It is old magic from the days when his race was more numerous and feared hunger more than extinction at the hands of their prey. It does not understand that Felix does not want to kill his victim. In the open ocean, there are only three directions; north, south, and towards Sylvain. Instead of lines, he swims in massive loops, an indecisive orbit around one point.

He sleeps in wrecks of old sailing ships now; they hide him in their broken bellies, their rotting ribcages. Maybe he’s just used to being around humans, too domesticated for rocks and reefs to be sufficient shelter. 

Felix has dreams, too.

He dreams of the glass tank he was kept in for months, too narrow to turn around in with thick irons bars over the top, and the instruments those men jammed into his body to draw out his precious tears. He dreams of the coffin that Lysithea smuggled him out in and of the long hours laying in the dark alongside the withered corpse, jostled and carried and left to rot until finally they were tossed into the sea.

But now, he also dreams of a human man with russet hair and warm eyes; of calloused hands stroking carefully along scarred skin; of a gentle, bitter smile as he hands Felix a glass flute.

Sometimes, the good dreams are worse than the nightmares.

* * *

  
It's just past midday when he tastes the blood. 

He’s following a crab along the sea floor, testing out a new tune on his flute. Underwater, the music isn’t as sharp and clear, but he likes it better. It surrounds him down here.

A flicker of his fingers and a water-borne blow and the crab dances across the sand, Thralled completely. Felix opens his mouth for the next gulp of water and tastes a hint of iron in the current.

Another taste tells him it’s blood. Human blood, and _familiar._ Felix freezes, fins fanning out to suspend him in the water. He focuses, consciously, for the first time on the pull of the mermaid mark. 

There.

It could be nothing. A splinter lodged under Sylvain’s skin pulled free, a hangnail, a rope burn. It’s just a trace. 

Felix scents again, drawing more water through his gills, and tastes more. Sylvain said he didn’t die easily, that he knows how to hold his own in a fight. Felix doesn’t have to follow. He doesn’t owe him anything.

Movement on the sand below him spurs him to action, and with a furious movement he dives, catching the crab and biting it in half.

_You will be missed._

He wants to scream, but he can’t. Humans took that away so they could use his body better for their cursed experiments. He hates them all, with no exceptions. The only thing that pulls him to Sylvain is the mark of unfinished business. Isn’t it?

Even the crustacean in his mouth can’t wipe away the hint of human blood, the memory of hands on his body meant to soothe not sting, the weight of the flute around his neck. And he swallows it and his pride as he follows the pull of the mark and the wisps of diluted blood.

* * *

Splintered wood rotting in the waves tells a grim tale, even to a creature of the ocean. Felix has been swimming just below the surface of the water for a day straight. At first he’d jumped every so often to look above the waves, searching for a familiar sail, but he’s too tired now; lifting his head is all he can do. The first signs of a wrecked ship, however, lend energy to his movements.

He leaps, once, to confirm his heading and doubles his pace.

The sight of Sylvain’s ship in pieces on the sandbar makes Felix’s stomach churn. It’s barely an islet, a half dozen trees at most, but he can see the distant shape of humans moving along the shore.

Sylvain isn’t one of them. He can feel him somewhere, elsewhere, beyond. With more caution now, Felix approaches, following the waves crashing along the shore. Slinking along the damp sand until he can make out voices.

“...fire once the wood dries a little more, maybe we’ll be able to signal for help.”

“What help, Ashe? We’re halfway to Morfis by now! We— I—“

“Yelling at him won’t help. Augh—- no, don’t touch it. Leave it be.”

“I’m trying to help—“

“It’ll bleed faster if you do. Here, I’ll make bandages.”

By their voices, he counts them. One, two, three, four, five, six. Everyone, alive, except Sylvain; the one he wants to see most.

Satisfied they’re safe for now, Felix slithers back into the ocean, doubling his speed. He doesn’t bother to check the surface anymore; the mermaid mark pulls him along, and his anger fuels him.

Whoever did this, did it to hurt Sylvain. For that, he will make the sea run red with their blood.

The sun has just set by the time he finds the ship; larger than the fishing vessel on which he had spent so many happy weeks. His teeth tingle, remembering sinking into human flesh. Sylvain is aboard here. He can feel it, and he can taste the blood in the water.

Concealed in the shadow of the ship, Felix makes no noise as he breaks the surface. Above him, the ship slumbers; the only sound is a single set of footsteps and a low, gentle whistle. A guard.

Felix waits until he can see the shadow of the sailor, flickering in the lamp light on the surface of the sea, to raise his flute to his lips. Three careful notes, laced with intent, as he stares at the shadow.

It stops. And stays, as Felix willed, perfectly still.

Silent, Felix shapeshifts away his tail and climbs up the side of the vessel, sharp nails digging into the wooden timbers. The guard is waiting for him, complacent and unseeing, and follows Felix easily into the shadows. He doesn’t struggle as his throat is slit with his own sword, then Felix strips the guard’s body and eases it over the side.

In disguise, the glass flute hidden under a borrowed shirt, Felix resumes the dead guard’s circuit. 

He doesn’t have the strength to Thrall the entire ship at once. He’ll have to pick them off, one at a time, as he goes. At least until he finds Sylvain.

The mermaid mark calls him below decks, to the dark levels below the boisterous dining hall and the half-empty crew’s quarters. Down, down, to where the air is cold, sour with mildew, and sharp with blood.

Here, a quartet of cells sit with bilge water sloshing across the floor. Three stand empty, and the fourth holds a man on his knees, his red hair leeched of warmth and color in the gloom. Felix’s heart skips a beat.

Another pair of guards, and one turns at the soft sound of bare footsteps. “Oi,” he calls, “th’ hell are you doing down here?”

Felix pulls the flute out of his shirt and, just as a drinking song breaks out above them, begins to play.

_“My true love, she is beautiful, my true love she is young!”_

Seamless, he matches his melody to their coarse tune, and every head turns his way.

_“Her eyes are as blue as the violet's hue, and silvery sounds her tongue!”_

As before, the sailors are putty in his hands - offering their weapons as Felix’s flute trills commands. Even the prisoner is pressed against the bars at his song, reaching for the siren with frantic hands—

With _one_ frantic hand.

Felix ignores the Thralled guards to cross the soaking wet deck, his hands shaking as he lowers the flute. Sylvain stares at him with golden, unfocused eyes and a vacant grin; seeing without seeing.

There’s no putting it off now. He can’t rescue Sylvain if he is under Felix’s Thrall. He’ll have to cure him; of everything. Including that first, essential promise.

_I swear to return you to the ocean alive._

Felix threads his fingers through Sylvain’s remaining ones, pressing their palms together. Traces the ugly, unbandaged stump on the other arm. Sylvain doesn’t flinch, even as fresh blood weeps from the swollen flesh.

“Forgive me,” Felix whispers, and he presses their lips together.

For a moment, it’s nauseating; cold, immobile lips frozen in a grin against his mouth. Then, as the magic seeps between them, Sylvain thaws and reciprocates. He squeezes Felix’s hand, pressing urgently against the bars as the kiss deepens, his tongue chasing Felix’s own and nicking Felix’s teeth. The iron tang sets Felix’s blood ablaze.

“Felix?”

At the sound of his name, he pulls back. Finally, Sylvain is looking at him, seeing him, dark brown eyes wide with joy. And then, horror.

“Felix,” he whispers with an edge of panic, “you need to get out of here.”

“So do you.” Felix takes a step back, patting the guard’s clothes down, and fishes out a key. 

“No, you don’t understand. It’s my half brother Miklan, he’s a sell sword, and he—“

He presses a finger to Sylvain’s lips, glaring. “Don’t care,” he hisses, and hands Sylvain one of the offered swords. “Follow. Quietly.”

They lock these men in Sylvain’s cell after their pantomimed argument, and hurry back up the stairs. Most of the crew are celebrating the day’s events, and it puts Sylvain even more on edge. 

Just as they start to untie a rowboat, a bell rings out from above them.

“The prisoner has escaped! The prisoner has escaped!”

In the crows nest, a sailor calls the alarm. Sylvain swears and hacks at the hoisting rope with his sword.

“Shit, shit, shit. Felix, I warned you, it wasn’t about me. Get overboard, now! I’ll follow you, I promise!”

Felix doesn’t have time to Thrall out the truth in him, nor could he anymore. With his kiss, Sylvain is immune. But he doesn’t need to Thrall him to know that those words are lies, and Sylvain will go down fighting if Felix leaves him.

So instead, as the decks are flooded with well-armed sailors, Felix reaches deep inside himself for every last drop of magic in him. And one more time, he begins to play.

No simple three note request, no mirrored shanty melody. This is a song as old as the shape shifting Saints, hummed under the waves by his kin for centuries. Older than the mermaid mark on Sylvain’s hand, that with the kiss has faded to a simple scar.

Every man on the ship stops dead.

Without looking away, Felix nods to the lifeboats. Sylvain, hesitant at first, resumes untying the complex knots as Felix continues to play. Sweat beads on his brows, then blood drips down from his nose to his lips. Scales sprout along his back, his legs fighting to reform back into a tail, but he doesn’t falter. He holds steady, Thralling the scores and scores of bloodthirsty humans.

And then something shifts from inside the crowd; someone moves against his will. Felix has just long enough to realize what that might mean before the glass flute is shattered, its melody lost to the discordant boom of a gunshot.

“Well, well. It’s been a while since we saw each other, hasn’t it been? My little fishy friend?”

Two figures emerge from the crowd; a man holding a gun who looks oddly similar to Sylvain, and a woman with blood-red hair. As he watches, the latter smiles and shape-shifts to reveal ashen skin and dark-ringed eyes.

He knows them. He’d only seen the man through the glass of his tank once or twice, but the woman had been an experiment like Lysithea. A chimera, made with the blood of a siren who had come before him.

He hadn’t known the experiment had been a success.

“Mikky, darling,” Kronya purrs, pressing a kiss on the red-haired man’s cheek, “your baby brother has been lovely bait.”

“Half brother.” He loads another bullet into his gun, and fires it.

Felix is frozen, his freedom shattered in his hands and raining shards of glass onto the deck. He knows they won’t kill him. It would be too kind. But the bullet never hits him.

Something yanks him backwards; a wet crunch follows, a gasp of pain. And then Sylvain, standing between the crew and Felix, staggers and crumples to his knees with bright blood blooming across his chest.

Grief and the weight of Sylvain’s body pull Felix to his knees. Cradling Sylvain in his arms, he stares into those dark brown eyes, one question unvoiced hanging between them.

“I…” Blood seeps between Sylvain’s teeth as he forces a smile. “I promised…”

But Felix had cured him of that. He’d lied to his country, to those Adrestian guards, to his own crew to keep Felix safe. But those words, that offer to save the life of someone as dangerous and damaged as a siren - those he had meant?

Boots click across the wooden deck, and then a shadow casts itself over them both.

“How cute!” mocks Kronya, leaning over them. “What a noble death. Pity it’s all for nothing.”

Felix eases Sylvain onto the deck, reaching for the shattered flute, fury building in him. Kronya scoffs.

“I would love to see you try to carry a tune _now,_ my little mute—“

Her last words are cut off in a scream. Quick as lightning, Felix jams the shattered end of the flute into her eye. She stumbles forward, blood splattering across Sylvain’s still form, and Felix lunges up to meet her. Razor sharp teeth meet in her neck, crunching through muscle and cartilage alike to tear her throat out.

Kronya falls backwards, choking for air. Red sparks of magic flare from the injury as she begins to regenerate. But Felix is ready, has been ready since the first time she jammed a knife into his side and cackled as his precious blood welled from the wound, since the first time she twisted it to wring out a tear. With one swift slice of Sylvain’s borrowed sword, he severs her head from her body.

And then he turns to the crew.

Their eyes glow golden, like dozens of ground bound stars. Their attention is fixed on him, waiting for a command.

Felix points the dripping sword, which shakes in his exhausted hand, at Miklan and grinds out three words.

_“Tear him apart!”_

As one, the Thralled crew turn on their captain. As one, they swarm like ants on a carcass. Felix hears the first shots ring out, but it’s not his concern. 

With effort, he drags Sylvain into the rowboat; cuts them free and lowers them into the ocean, far from the screams as Miklan runs out of ammunition.

“Sylvain?” Felix whispers, shifting back into his true form and laying next to his human - his captain, his lover, his friend. “Sylvain?”

There is no answer. He lays, still and cold, in the bottom of the boat.

Above them, cold and unfeeling, the moon pours pale light over Sylvain’s body; casting his form in snow-cold highlights and despair-deep shadows, exaggerating every feature and flaw. Felix, as he did before an eternity ago, eases himself on top of the body to shield it from such unforgiving light.

One last kiss, on lips that will never smile again. And Felix presses his face into Sylvain’s neck to grieve. A lone tear, small and uncertain from years of misuse, curves down his cheek to sink into the center of the crimson stain on Sylvain’s shirt.

And then he hears it. A heartbeat.

Felix raises his head and watches, hardly daring to breathe, as Sylvain opens his eyes. He looks down at Felix and, weak but sure, a grin twists his mouth.

“Hey,” he whispers.

A few more tears fall, gentle as a spring rain, and Felix surges up to meet him.

* * *

  
With Sylvain guiding and Felix pulling the little boat, they make it to a port. Leicester Alliance, apparently - Felix has never paid attention to human territory. He might have to now, though, since he intends to spend his life with one. No magical marks, no chain, no binding promises; he simply loves him, and is loved in return.

Felix and Sylvain row the rest of their way to the docks, weaving between substantially bigger ships, and no sooner have they tied their vessel up than a familiar voice shouts down at them.

“Captain?! Captain, is that you?”

From the deck of a massive ship, Alois is waving frantically. He’s not alone, either. The entire crew is there, plastered to the rail and cheering. Ashe even swan-dives into the water and swims to meet them, slapping Sylvain on the shoulder.

“Don’t do that to us again,” he chides between gasps of breath. “Felix - this was your doing, wasn’t it?”

Guilt stirs in his chest, igniting easily into anger. It’s not his fault, being born with valuable blood. But then Ashe continues:

“You saved him, right?”

Felix swallows and nods.

Ashe places a hand on Felix’s shoulder and locks eyes with him. “Thank you,” he says, soft and sincere. “I— hope you stick around.”

“Oh, I think he will,” Sylvain smiles, with entirely too much confidence. He may be right, but on principle Felix wants to kick him right back into the ocean for that smug expression. “How did you survive?”

Ashe starts in on something complicated, rattling off ship terms and technical terms that Felix can’t follow. As his attention drifts, it lands on the man and woman stepping off of the rescuing ship. The man himself is medium-skinned and handsome, but there’s something about his companion that has the hairs on the back of Felix’s neck standing up. A pull, like the mermaid mark. The draw of old magic.

The man catches Felix’s eye and waves, a smile to give even Sylvain’s a run for his money, but the woman only stares. Her pale green eyes, vivid as the shallow tropical oceans of Almyra, study him.

A dip of her head and she melts into the crowd.

“...gotten out alive if it hadn’t been for Captain Von Reigan. He even recovered your bathtub.”

“Did he really? Huh. We’ll have to thank him for it later. For now, let’s just find a place to sleep, all right? We’ll try to sort out a new ship and whatnot in the morning. Does that work for you?”

A pause. Felix comes back to the moment in timeto realize he is being addressed. He nods.

Sylvain claps his hands and ushers his crew along the dock, laughing at a joke from Caspar and playfully dismissing a scold from Alois. As they walk, he falls back to walk in step with Felix and winds an arm around his waist.

“Hey.”

The smile he presses to Felix’s neck is much more gentle than the ones before, and is accompanied by a gentle, purring trill.

“I love you,” he whispers into Felix’s ear.

Felix replies with a kiss.

  
  
  
  


**Notes for the Chapter:**

> Sylvain reading to Felix - https://twitter.com/saffli/status/1328553998522126336?s=21
> 
> The Kiss Scene - https://twitter.com/b4k95/status/1339716236599562240?s=21
> 
> Felix flicking water at Sylvain from his tub - https://twitter.com/eggyankee/status/1335765537088020480?s=21


End file.
